fix(auth/users): close MED-11 lying field — DeactivatedAt loaded + enforced on login (A-2)

The MED-11 closure shipped users.deactivated_at + DELETE /api/v1/auth/users/{id}
+ cascade-revoke, but the federated-user soft-delete was reversible: the next
OIDC login under the same (provider, subject) tuple re-minted a session and
re-elevated the user.

Three legs of the chain were severed (each independently CRIT-shaped):

  Leg A — postgres/user.go::userColumns omitted `deactivated_at`, so scanUser
          never populated User.DeactivatedAt. Every Get / GetByOIDCSubject /
          ListAll returned DeactivatedAt = nil regardless of the column value.

  Leg B — postgres/user.go::Update SQL omitted `deactivated_at = $X`, so the
          handler's `u.DeactivatedAt = now()` mutation was a no-op write at
          the SQL level. Even with leg A closed, no row ever flipped.

  Leg C — oidc/service.go::upsertUser did not inspect DeactivatedAt on the
          existing-user path. Even with legs A + B closed, the OIDC login
          would still proceed normally.

The cascade-session-revoke half of the original closure remained correct, but
only for the duration of the user's current cookie. SOC 2 CC6.3 + ISO 27001
A.9.2.6 "user access removal" controls require both immediate revoke AND
persistent block — this fix restores the persistent-block leg.

Closure across layers:

  internal/repository/postgres/user.go
    - userColumns adds `deactivated_at`
    - scanUser reads via sql.NullTime intermediate (column is nullable)
    - Create writes deactivated_at explicitly (NULL for new active users;
      forward-compat for future seed-data flows that pre-populate the column)
    - Update writes deactivated_at on every call; nil DeactivatedAt → NULL
      (supports reactivation)

  internal/auth/oidc/service.go
    - New sentinel ErrUserDeactivated
    - upsertUser checks existing.DeactivatedAt != nil BEFORE mutating email /
      display_name / last_login_at — preserves last_login_at forensics on
      rejected login attempts (defense-in-depth pin against future
      "performance optimization" that reorders the gate)

  internal/api/handler/auth_session_oidc.go
    - classifyOIDCFailure adds typed errors.Is dispatch for ErrUserDeactivated
      → audit category "user_deactivated" (SOC/SIEM observability surface)

  internal/api/handler/auth_users.go
    - Self-deactivate guard on Deactivate: HTTP 409 + audit row
      auth.user_deactivate_self_rejected when caller targets own User row.
      Prevents an admin from one-way-door locking themselves out via the
      standard handler; break-glass remains the recovery path.
    - New Reactivate handler: inverse of Deactivate. Clears DeactivatedAt
      via Update; emits auth.user_reactivated audit row. Idempotent on
      already-active rows. Sessions revoked at deactivation stay revoked
      (cascade irreversible by design — user must complete fresh OIDC
      login).

  internal/api/router/router.go
    - POST /api/v1/auth/users/{id}/reactivate wired with auth.user.deactivate
      gate (reactivation is the inverse op, not a separate privilege)

  web/src/api/client.ts + web/src/pages/auth/UsersPage.tsx
    - authReactivateUser() client function
    - Reactivate button on deactivated rows in UsersPage

Regression coverage:

  Postgres (testcontainers, skipped under -short):
    TestUserRepository_DeactivatedAt_RoundTrip — Create → set DeactivatedAt
      → Update → Get / GetByOIDCSubject / ListAll round-trip the value
    TestUserRepository_DeactivatedAt_CreateWritesNullForActive — new active
      user reads back DeactivatedAt = nil
    TestUserRepository_DeactivatedAt_CreatePersistsPreDeactivated — Create
      with non-nil DeactivatedAt round-trips (forward-compat path)

  OIDC service:
    TestService_HandleCallback_RejectsDeactivatedUser — errors.Is
      ErrUserDeactivated; CallbackResult nil; persisted email / last_login_at
      / deactivated_at NOT mutated by the rejected attempt
    TestService_HandleCallback_AllowsReactivatedUser — DeactivatedAt = nil
      → happy path resumes
    TestService_HandleCallback_DeactivatedUserPreservesForensics —
      defense-in-depth pin against future regressions that reorder the
      gate-vs-mutation sequence

  Classifier:
    TestClassifyOIDCFailure extended — typed dispatch + wrapped variant
      round-trip through errors.Is

  Handler:
    TestAuthUsers_Deactivate_RejectsSelfDeactivate — HTTP 409 + audit
      row + cascade-revoke NOT fired + row stays active
    TestAuthUsers_Deactivate_OtherUser_HappyPath — HTTP 204 + cascade
      fires + row soft-deleted
    TestAuthUsers_Reactivate_HappyPath / _IdempotentOnActiveUser /
      _UnknownID / _MissingID / _UpdateError

Phase 6 verify gate green on the targeted packages: gofmt clean, go vet
clean, go test -short pass across internal/auth/oidc, internal/api/handler,
internal/api/router, internal/repository/postgres, internal/auth/...,
internal/service/..., internal/tlsprobe/..., internal/trustanchor/...,
internal/validation/...

Spec at cowork/auth-bundles-fixes-2026-05-11/02-crit-deactivated-at-enforcement.md
Closure annotation at cowork/auth-bundles-audit-2026-05-10.md MED-11 row.
Operator advisory in CHANGELOG.md v2.1.0 release notes.

CHANGELOG.md

@@ -4,6 +4,33 @@
 
 ### Security (BREAKING)
 
+- **Federated-user deactivation now actually blocks login (Audit 2026-05-11 A-2).**
+  The MED-11 closure shipped `users.deactivated_at` + `DELETE /api/v1/auth/users/{id}`
+  + cascade-session-revoke, but the column was a "lying field" three legs over: the
+  postgres user repository never SELECTed it (so `User.DeactivatedAt` always read
+  nil), the `Update` SQL never wrote it (so the handler's mutation was a no-op),
+  and the OIDC `upsertUser` path never checked it (so the next login under the
+  same `(provider, subject)` tuple re-minted a session and re-elevated the user).
+  The cascade-revoke remained correct for the current cookie only. **Operator
+  advisory: if you deactivated a federated user between the MED-11 closure
+  (Bundle 2 merge `dea5053`) and the v2.1.0 release tag, verify the user cannot
+  OIDC-log-in after upgrading — the column took no effect at login time before
+  this fix. If needed, re-run the deactivation against the upgraded server.**
+  Closure: `userColumns` + `scanUser` now read `deactivated_at` via `sql.NullTime`;
+  `Create` + `Update` write it explicitly; `upsertUser` returns the new
+  `ErrUserDeactivated` sentinel before mutating fields (preserves `last_login_at`
+  forensics on rejected logins); `classifyOIDCFailure` surfaces the rejection
+  as audit category `user_deactivated`. Self-deactivate guard on
+  `DELETE /api/v1/auth/users/{id}` returns HTTP 409 + audit row
+  `auth.user_deactivate_self_rejected` (prevents an admin from one-way-door
+  locking themselves out via the standard handler — break-glass remains the
+  recovery path). New inverse endpoint `POST /api/v1/auth/users/{id}/reactivate`
+  (gated `auth.user.deactivate` — reactivation is the inverse op, not a separate
+  privilege) clears `deactivated_at`; emits audit row `auth.user_reactivated`.
+  Sessions revoked at deactivation stay revoked across reactivation — the user
+  must complete a fresh OIDC login. GUI: `UsersPage.tsx` now renders a Reactivate
+  button on deactivated rows. CWE-862 (missing authorization at the user-state
+  boundary). SOC 2 CC6.3 + ISO 27001 A.9.2.6 compliance-table-flipping fix.
 - **`__Host-` cookie prefix on all three auth cookies (Audit 2026-05-10 MED-14).**
   The session cookie, CSRF cookie, and OIDC pre-login cookie are renamed from
   `certctl_session` / `certctl_csrf` / `certctl_oidc_pending` to

internal/api/handler/auth_session_oidc.go

@@ -1006,11 +1006,11 @@ func (h *AuthSessionOIDCHandler) TestProvider(w http.ResponseWriter, r *http.Req
 	}
 	h.recordAudit(r.Context(), "auth.oidc_provider_tested", caller.ActorID, caller.ActorType, "",
 		map[string]interface{}{
-			"issuer_url":           req.IssuerURL,
-			"discovery_succeeded":  res.DiscoverySucceeded,
-			"jwks_reachable":       res.JWKSReachable,
-			"iss_param_supported":  res.IssParamSupported,
-			"error_count":          len(res.Errors),
+			"issuer_url":          req.IssuerURL,
+			"discovery_succeeded": res.DiscoverySucceeded,
+			"jwks_reachable":      res.JWKSReachable,
+			"iss_param_supported": res.IssParamSupported,
+			"error_count":         len(res.Errors),
 		})
 	writeJSON(w, http.StatusOK, res)
 }
@@ -1267,6 +1267,14 @@ func classifyOIDCFailure(err error) string {
 		return "prelogin_ua_mismatch"
 	case errors.Is(err, oidcsvc.ErrPreLoginIPMismatch):
 		return "prelogin_ip_mismatch"
+	// Audit 2026-05-11 A-2 — surface deactivated-user rejection as its
+	// own audit category so SOC / SIEM can alert on attempted logins by
+	// federated users that the admin has soft-deleted. Typed dispatch
+	// (not substring) because the sentinel is the only authoritative
+	// test for this condition; the message string is implementation
+	// detail subject to change.
+	case errors.Is(err, oidcsvc.ErrUserDeactivated):
+		return "user_deactivated"
 	}
 	msg := strings.ToLower(err.Error())
 	switch {

internal/api/handler/auth_session_oidc_test.go

@@ -1217,6 +1217,11 @@ func TestClassifyOIDCFailure(t *testing.T) {
 		// Wrapped variants must round-trip through errors.Is.
 		{fmt.Errorf("upstream: %w", oidcsvc.ErrIssParamMissing), "iss_param_missing"},
 		{fmt.Errorf("upstream: %w", oidcsvc.ErrIssParamMismatch), "iss_param_mismatch"},
+		// Audit 2026-05-11 A-2 — deactivated-user rejection is its own
+		// audit category (typed dispatch; wrapped variant must also
+		// round-trip).
+		{oidcsvc.ErrUserDeactivated, "user_deactivated"},
+		{fmt.Errorf("upstream: %w", oidcsvc.ErrUserDeactivated), "user_deactivated"},
 		{errors.New("some other error"), "unspecified"},
 	}
 	for _, tc := range cases {

internal/api/handler/auth_users.go

@@ -115,6 +115,24 @@ func (h *AuthUsersHandler) Deactivate(w http.ResponseWriter, r *http.Request) {
 		Error(w, http.StatusBadRequest, "missing user id")
 		return
 	}
+	// Audit 2026-05-11 A-2 — self-deactivate guard. An admin that
+	// deactivates their own User row immediately invalidates their next
+	// login (upsertUser at internal/auth/oidc/service.go rejects with
+	// ErrUserDeactivated); the cascade-revoke then kicks them out of the
+	// active session, leaving the tenant without an admin able to
+	// reactivate themselves. Break-glass credentials (Bundle 2 Phase 7.5)
+	// remain the recovery path, but the operator should not be able to
+	// trip the foot-gun through the standard handler. 409 (not 403) —
+	// the request is well-formed and authenticated; the conflict is
+	// between the action and the actor's own identity. Audit row records
+	// the rejection so an upstream SIEM can spot accidental triggers.
+	if caller.ActorType == domain.ActorTypeUser && caller.ActorID == id {
+		_ = h.audit.RecordEventWithCategory(r.Context(), caller.ActorID, caller.ActorType, "auth.user_deactivate_self_rejected",
+			domain.EventCategoryAuth, "user", id,
+			map[string]interface{}{"user_id": id, "reason": "self_deactivate_blocked"})
+		Error(w, http.StatusConflict, "cannot deactivate your own account; use break-glass recovery or have another admin act")
+		return
+	}
 	u, gerr := h.users.Get(r.Context(), id)
 	if gerr != nil {
 		if errors.Is(gerr, repository.ErrUserNotFound) {
@@ -157,6 +175,67 @@ func (h *AuthUsersHandler) Deactivate(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusNoContent)
 }
 
+// Reactivate clears users.deactivated_at, allowing the federated user
+// to log in again via their OIDC provider. The next OIDC callback for
+// the (provider_id, subject) tuple goes through upsertUser, which now
+// passes the DeactivatedAt == nil gate, and the user's account
+// information (email, display_name, last_login_at) updates normally.
+//
+// Audit 2026-05-11 A-2 — Reactivate is the inverse of Deactivate. The
+// original MED-11 closure only shipped Deactivate; with A-2 closure the
+// DeactivatedAt field now actually gates login, so the operator needs a
+// supported way to undo a soft-delete without hand-editing the database.
+//
+// Gate: same auth.user.deactivate permission. Reactivation is the
+// inverse op, not a separate privilege — anyone who can deactivate must
+// be able to undo their own mistake.
+//
+// Idempotent: reactivating an already-active user returns 204 with no
+// row write.
+//
+// No session-side-effect: reactivation does NOT mint a session. The
+// user must complete a fresh OIDC login through their provider; sessions
+// from before the deactivation stay revoked (the cascade-revoke in
+// Deactivate is irreversible by design).
+func (h *AuthUsersHandler) Reactivate(w http.ResponseWriter, r *http.Request) {
+	caller, err := callerFromRequest(r)
+	if err != nil {
+		writeAuthError(w, err)
+		return
+	}
+	id := r.PathValue("id")
+	if id == "" {
+		Error(w, http.StatusBadRequest, "missing user id")
+		return
+	}
+	u, gerr := h.users.Get(r.Context(), id)
+	if gerr != nil {
+		if errors.Is(gerr, repository.ErrUserNotFound) {
+			Error(w, http.StatusNotFound, "user not found")
+			return
+		}
+		Error(w, http.StatusInternalServerError, "could not load user")
+		return
+	}
+	// Idempotent: reactivating an already-active user is a no-op.
+	if u.DeactivatedAt == nil {
+		w.WriteHeader(http.StatusNoContent)
+		return
+	}
+	u.DeactivatedAt = nil
+	if uerr := h.users.Update(r.Context(), u); uerr != nil {
+		Error(w, http.StatusInternalServerError, "could not reactivate user")
+		return
+	}
+	_ = h.audit.RecordEventWithCategory(r.Context(), caller.ActorID, caller.ActorType, "auth.user_reactivated",
+		domain.EventCategoryAuth, "user", u.ID,
+		map[string]interface{}{
+			"user_id":          u.ID,
+			"oidc_provider_id": u.OIDCProviderID,
+		})
+	w.WriteHeader(http.StatusNoContent)
+}
+
 // =============================================================================
 // MED-12 — Auth runtime config read endpoint.
 // =============================================================================

internal/api/handler/auth_users_test.go

@@ -0,0 +1,297 @@
+package handler
+
+// Audit 2026-05-11 A-2 closure — federated-user admin handler test
+// surface. Covers the self-deactivate guard, reactivate happy-path /
+// idempotent / 404 branches, and the audit-event shape.
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	userdomain "github.com/certctl-io/certctl/internal/auth/user/domain"
+	"github.com/certctl-io/certctl/internal/domain"
+	"github.com/certctl-io/certctl/internal/repository"
+)
+
+// stubFullUserRepo is a richer in-memory UserRepository than the one
+// in auth_session_oidc_test.go (which always returns ErrUserNotFound
+// from Get). The auth-users handler tests need round-trip semantics
+// across Get / Update.
+type stubFullUserRepo struct {
+	rows      map[string]*userdomain.User
+	updateErr error
+	getErr    error
+}
+
+func newStubFullUserRepo() *stubFullUserRepo {
+	return &stubFullUserRepo{rows: make(map[string]*userdomain.User)}
+}
+
+func (s *stubFullUserRepo) Get(_ context.Context, id string) (*userdomain.User, error) {
+	if s.getErr != nil {
+		return nil, s.getErr
+	}
+	if u, ok := s.rows[id]; ok {
+		// Defensive copy — Update path mutates the struct.
+		c := *u
+		if u.DeactivatedAt != nil {
+			t := *u.DeactivatedAt
+			c.DeactivatedAt = &t
+		}
+		return &c, nil
+	}
+	return nil, repository.ErrUserNotFound
+}
+
+func (s *stubFullUserRepo) GetByOIDCSubject(_ context.Context, _, _ string) (*userdomain.User, error) {
+	return nil, repository.ErrUserNotFound
+}
+
+func (s *stubFullUserRepo) Create(_ context.Context, u *userdomain.User) error {
+	s.rows[u.ID] = u
+	return nil
+}
+
+func (s *stubFullUserRepo) Update(_ context.Context, u *userdomain.User) error {
+	if s.updateErr != nil {
+		return s.updateErr
+	}
+	if _, ok := s.rows[u.ID]; !ok {
+		return repository.ErrUserNotFound
+	}
+	// Persist the struct (defensive copy of nullable timestamp).
+	c := *u
+	if u.DeactivatedAt != nil {
+		t := *u.DeactivatedAt
+		c.DeactivatedAt = &t
+	}
+	s.rows[u.ID] = &c
+	return nil
+}
+
+func (s *stubFullUserRepo) ListAll(_ context.Context, tenantID string) ([]*userdomain.User, error) {
+	out := make([]*userdomain.User, 0, len(s.rows))
+	for _, u := range s.rows {
+		if tenantID == "" || u.TenantID == tenantID {
+			out = append(out, u)
+		}
+	}
+	return out, nil
+}
+
+// stubRevoker records cascade-revoke calls.
+type stubRevoker struct {
+	called    bool
+	actorID   string
+	actorType string
+	revokeErr error
+}
+
+func (s *stubRevoker) RevokeAllForActor(_ context.Context, actorID, actorType string) error {
+	s.called = true
+	s.actorID = actorID
+	s.actorType = actorType
+	return s.revokeErr
+}
+
+// stubAuditRecorder collects event actions for assertion.
+type stubAuditRecorder struct {
+	events []string
+	last   map[string]interface{}
+}
+
+func (s *stubAuditRecorder) RecordEventWithCategory(_ context.Context, _ string, _ domain.ActorType, action, _, _, _ string, details map[string]interface{}) error {
+	s.events = append(s.events, action)
+	s.last = details
+	return nil
+}
+
+func newSeededUser(id string, deactivatedAt *time.Time) *userdomain.User {
+	return &userdomain.User{
+		ID:                  id,
+		TenantID:            "t-default",
+		Email:               id + "@example.test",
+		DisplayName:         id,
+		OIDCSubject:         "sub-" + id,
+		OIDCProviderID:      "op-x",
+		LastLoginAt:         time.Now().UTC(),
+		WebAuthnCredentials: []byte("[]"),
+		CreatedAt:           time.Now().UTC(),
+		UpdatedAt:           time.Now().UTC(),
+		DeactivatedAt:       deactivatedAt,
+	}
+}
+
+// =============================================================================
+// Self-deactivate guard (Audit 2026-05-11 A-2)
+// =============================================================================
+
+func TestAuthUsers_Deactivate_RejectsSelfDeactivate(t *testing.T) {
+	users := newStubFullUserRepo()
+	users.rows["u-admin"] = newSeededUser("u-admin", nil)
+	rev := &stubRevoker{}
+	audit := &stubAuditRecorder{}
+	h := NewAuthUsersHandler(users, rev, audit, "t-default")
+
+	req := httptest.NewRequest(http.MethodDelete, "/api/v1/auth/users/u-admin", nil)
+	req.SetPathValue("id", "u-admin")
+	req = withActor(req, "u-admin", string(domain.ActorTypeUser))
+	w := httptest.NewRecorder()
+	h.Deactivate(w, req)
+
+	if w.Code != http.StatusConflict {
+		t.Errorf("status = %d; want 409", w.Code)
+	}
+	// Cascade-revoke must NOT have fired.
+	if rev.called {
+		t.Error("RevokeAllForActor was called on a self-deactivate; the guard must short-circuit before cascade")
+	}
+	// Row must still be active.
+	row, _ := users.Get(context.Background(), "u-admin")
+	if row.DeactivatedAt != nil {
+		t.Error("user row was deactivated despite the self-deactivate guard")
+	}
+	// Audit row must record the rejection.
+	found := false
+	for _, e := range audit.events {
+		if e == "auth.user_deactivate_self_rejected" {
+			found = true
+			break
+		}
+	}
+	if !found {
+		t.Errorf("audit events missing self-reject marker: %v", audit.events)
+	}
+}
+
+func TestAuthUsers_Deactivate_OtherUser_HappyPath(t *testing.T) {
+	users := newStubFullUserRepo()
+	users.rows["u-admin"] = newSeededUser("u-admin", nil)
+	users.rows["u-target"] = newSeededUser("u-target", nil)
+	rev := &stubRevoker{}
+	audit := &stubAuditRecorder{}
+	h := NewAuthUsersHandler(users, rev, audit, "t-default")
+
+	req := httptest.NewRequest(http.MethodDelete, "/api/v1/auth/users/u-target", nil)
+	req.SetPathValue("id", "u-target")
+	req = withActor(req, "u-admin", string(domain.ActorTypeUser))
+	w := httptest.NewRecorder()
+	h.Deactivate(w, req)
+
+	if w.Code != http.StatusNoContent {
+		t.Errorf("status = %d; want 204", w.Code)
+	}
+	if !rev.called || rev.actorID != "u-target" || rev.actorType != string(domain.ActorTypeUser) {
+		t.Errorf("cascade-revoke did not fire correctly: called=%v id=%q type=%q",
+			rev.called, rev.actorID, rev.actorType)
+	}
+	row, _ := users.Get(context.Background(), "u-target")
+	if row.DeactivatedAt == nil {
+		t.Error("user row was not soft-deleted")
+	}
+}
+
+// =============================================================================
+// Reactivate (Audit 2026-05-11 A-2)
+// =============================================================================
+
+func TestAuthUsers_Reactivate_HappyPath(t *testing.T) {
+	now := time.Now().UTC()
+	users := newStubFullUserRepo()
+	users.rows["u-target"] = newSeededUser("u-target", &now)
+	audit := &stubAuditRecorder{}
+	h := NewAuthUsersHandler(users, &stubRevoker{}, audit, "t-default")
+
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/auth/users/u-target/reactivate", nil)
+	req.SetPathValue("id", "u-target")
+	req = withActor(req, "u-admin", string(domain.ActorTypeUser))
+	w := httptest.NewRecorder()
+	h.Reactivate(w, req)
+
+	if w.Code != http.StatusNoContent {
+		t.Errorf("status = %d; want 204", w.Code)
+	}
+	row, _ := users.Get(context.Background(), "u-target")
+	if row.DeactivatedAt != nil {
+		t.Errorf("user row still deactivated after reactivate: %v", row.DeactivatedAt)
+	}
+	// Audit row.
+	if len(audit.events) == 0 || audit.events[len(audit.events)-1] != "auth.user_reactivated" {
+		t.Errorf("audit events missing reactivate marker: %v", audit.events)
+	}
+}
+
+func TestAuthUsers_Reactivate_IdempotentOnActiveUser(t *testing.T) {
+	users := newStubFullUserRepo()
+	users.rows["u-target"] = newSeededUser("u-target", nil) // already active
+	audit := &stubAuditRecorder{}
+	h := NewAuthUsersHandler(users, &stubRevoker{}, audit, "t-default")
+
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/auth/users/u-target/reactivate", nil)
+	req.SetPathValue("id", "u-target")
+	req = withActor(req, "u-admin", string(domain.ActorTypeUser))
+	w := httptest.NewRecorder()
+	h.Reactivate(w, req)
+
+	if w.Code != http.StatusNoContent {
+		t.Errorf("status = %d; want 204", w.Code)
+	}
+	// Idempotent — no audit event for the no-op.
+	for _, e := range audit.events {
+		if e == "auth.user_reactivated" {
+			t.Errorf("reactivate emitted audit row on an already-active user (no-op should be silent)")
+		}
+	}
+}
+
+func TestAuthUsers_Reactivate_UnknownID(t *testing.T) {
+	users := newStubFullUserRepo()
+	audit := &stubAuditRecorder{}
+	h := NewAuthUsersHandler(users, &stubRevoker{}, audit, "t-default")
+
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/auth/users/u-missing/reactivate", nil)
+	req.SetPathValue("id", "u-missing")
+	req = withActor(req, "u-admin", string(domain.ActorTypeUser))
+	w := httptest.NewRecorder()
+	h.Reactivate(w, req)
+
+	if w.Code != http.StatusNotFound {
+		t.Errorf("status = %d; want 404", w.Code)
+	}
+}
+
+func TestAuthUsers_Reactivate_MissingID(t *testing.T) {
+	h := NewAuthUsersHandler(newStubFullUserRepo(), &stubRevoker{}, &stubAuditRecorder{}, "t-default")
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/auth/users//reactivate", nil)
+	// Intentionally do not SetPathValue — handler must reject the empty
+	// id with 400.
+	req = withActor(req, "u-admin", string(domain.ActorTypeUser))
+	w := httptest.NewRecorder()
+	h.Reactivate(w, req)
+
+	if w.Code != http.StatusBadRequest {
+		t.Errorf("status = %d; want 400", w.Code)
+	}
+}
+
+func TestAuthUsers_Reactivate_UpdateError(t *testing.T) {
+	now := time.Now().UTC()
+	users := newStubFullUserRepo()
+	users.rows["u-target"] = newSeededUser("u-target", &now)
+	users.updateErr = errors.New("postgres exploded")
+	h := NewAuthUsersHandler(users, &stubRevoker{}, &stubAuditRecorder{}, "t-default")
+
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/auth/users/u-target/reactivate", nil)
+	req.SetPathValue("id", "u-target")
+	req = withActor(req, "u-admin", string(domain.ActorTypeUser))
+	w := httptest.NewRecorder()
+	h.Reactivate(w, req)
+
+	if w.Code != http.StatusInternalServerError {
+		t.Errorf("status = %d; want 500", w.Code)
+	}
+}

internal/api/router/router.go

@@ -486,11 +486,16 @@ func (r *Router) RegisterHandlers(reg HandlerRegistry) {
 		}
 
 		// Audit 2026-05-10 MED-11 — federated-user admin surface.
+		// Audit 2026-05-11 A-2 — added reactivate route. Same permission
+		// gate as Deactivate (reactivation is the inverse op, not a
+		// separate privilege).
 		if reg.AuthUsers != nil {
 			r.Register("GET /api/v1/auth/users",
 				rbacGate(reg.Checker, "auth.user.read", reg.AuthUsers.List))
 			r.Register("DELETE /api/v1/auth/users/{id}",
 				rbacGate(reg.Checker, "auth.user.deactivate", reg.AuthUsers.Deactivate))
+			r.Register("POST /api/v1/auth/users/{id}/reactivate",
+				rbacGate(reg.Checker, "auth.user.deactivate", reg.AuthUsers.Reactivate))
 		}
 
 		// Audit 2026-05-10 MED-12 — auth runtime config read.

internal/auth/oidc/service.go

@@ -317,6 +317,21 @@ var (
 	// Audit 2026-05-10 MED-9 closure.
 	ErrProviderDisabled = errors.New("oidc: provider is disabled")
 
+	// ErrUserDeactivated signals the federated user row's
+	// `deactivated_at` is non-NULL. Audit 2026-05-11 A-2 closure —
+	// the deactivate flow at internal/api/handler/auth_users.go::Deactivate
+	// sets the column + cascade-revokes sessions, but pre-fix the OIDC
+	// login path never consulted it, so the very next login re-elevated
+	// the deactivated user. The check fires inside upsertUser before
+	// Update bumps last_login_at; an attempt to log in via OIDC after
+	// deactivation surfaces as audit `failure_category=user_deactivated`
+	// and the LoginPage's reason-aware error rendering shows the
+	// operator-friendly message.
+	//
+	// Reactivation surface: admin POSTs /api/v1/auth/users/{id}/reactivate
+	// (auth.user.deactivate perm) to clear the column.
+	ErrUserDeactivated = errors.New("oidc: user account is deactivated")
+
 	// ErrGroupsUnmapped: the user's groups don't match any of the
 	// operator's group_role_mappings for this provider. No session
 	// minted; audit row records auth.oidc_login_unmapped_groups.
@@ -809,6 +824,19 @@ func (s *Service) upsertUser(
 
 	existing, err := s.users.GetByOIDCSubject(ctx, provider.ID, subject)
 	if err == nil {
+		// Audit 2026-05-11 A-2 — refuse login for deactivated users.
+		// The admin `DELETE /api/v1/auth/users/{id}` flow sets
+		// `users.deactivated_at` + cascade-revokes existing sessions.
+		// Without this gate the very next OIDC login mints a fresh
+		// session and re-elevates. Compliance-table-flipping bug.
+		//
+		// Defense order: the check runs BEFORE the email / display-name
+		// mutation + last_login_at bump so a deactivated user's
+		// last_login_at field isn't silently updated by a rejected
+		// login attempt (forensics value).
+		if existing.DeactivatedAt != nil {
+			return nil, ErrUserDeactivated
+		}
 		// Update last_login_at, email, display_name (per the Phase 1
 		// mutable-field contract).
 		existing.Email = email

internal/auth/oidc/service_test.go

@@ -934,6 +934,172 @@ func TestService_UpsertUser_UpdateExistingPath(t *testing.T) {
 	}
 }
 
+// TestService_HandleCallback_RejectsDeactivatedUser pins the A-2
+// CRIT closure. A federated user whose `users.deactivated_at` is
+// non-nil must NOT be able to log in via OIDC; HandleCallback must
+// return ErrUserDeactivated BEFORE the email/display-name mutation
+// and last_login_at bump, and BEFORE the session mint.
+//
+// Audit 2026-05-11 A-2 — pre-fix, the deactivate handler set
+// `users.deactivated_at` on the in-memory struct, but: (a) the SQL
+// Update omitted the column so the write was a no-op; (b) the
+// postgres SELECT didn't include the column so even if (a) were
+// fixed scanUser returned DeactivatedAt = nil; (c) upsertUser never
+// looked at DeactivatedAt. The lying-field chain meant the very
+// next OIDC login re-elevated the user. This test pins the
+// service-layer leg of the closure (the SQL legs are pinned by
+// postgres/user_test.go).
+func TestService_HandleCallback_RejectsDeactivatedUser(t *testing.T) {
+	idp := newMockIdP(t)
+	users := newStubUsers()
+
+	// Pre-seed the user as deactivated. The default mockIdP subject
+	// is "test-subject"; the provider ID is "op-deact".
+	deactivatedAt := time.Now().UTC().Add(-1 * time.Hour)
+	prov := makeProvider(idp.URL(), "op-deact")
+	seeded := &userdomain.User{
+		ID:                  "u-deactivated",
+		TenantID:            prov.TenantID,
+		Email:               "deactivated@example.com",
+		DisplayName:         "Deactivated User",
+		OIDCSubject:         "test-subject",
+		OIDCProviderID:      "op-deact",
+		LastLoginAt:         time.Now().UTC().Add(-2 * time.Hour),
+		WebAuthnCredentials: []byte("[]"),
+		CreatedAt:           time.Now().UTC().Add(-24 * time.Hour),
+		UpdatedAt:           time.Now().UTC().Add(-1 * time.Hour),
+		DeactivatedAt:       &deactivatedAt,
+	}
+	users.byID[seeded.ID] = seeded
+	users.bySubject["op-deact:test-subject"] = seeded
+	originalLastLogin := seeded.LastLoginAt
+
+	pl := newStubPreLogin()
+	mappings := &stubMappings{roleIDs: []string{"r-operator"}}
+	sessions := &stubSessions{}
+	svc := NewService(&stubProviderLookup{provider: prov}, mappings, users, sessions, pl, "")
+
+	cookie, _, err := pl.CreatePreLogin(context.Background(), "op-deact", "deact-state", "test-nonce-fixed",
+		"v-deactiveeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee", "", "")
+	if err != nil {
+		t.Fatalf("CreatePreLogin: %v", err)
+	}
+
+	res, err := svc.HandleCallback(context.Background(), cookie, "code", "deact-state", "", "10.0.0.1", "Mozilla/5.0")
+	if !errors.Is(err, ErrUserDeactivated) {
+		t.Fatalf("err = %v; want ErrUserDeactivated", err)
+	}
+	if res != nil {
+		t.Errorf("CallbackResult should be nil on rejection, got %+v", res)
+	}
+
+	// Defense order pin — the rejected attempt must NOT have touched
+	// the persisted row's mutable fields. (Pre-fix the upsertUser
+	// path would update email + last_login_at first and only catch
+	// later; A-2 closure moves the check to the head of the function.)
+	row := users.byID["u-deactivated"]
+	if row.LastLoginAt != originalLastLogin {
+		t.Errorf("last_login_at advanced on rejected login: %v -> %v", originalLastLogin, row.LastLoginAt)
+	}
+	if row.Email != "deactivated@example.com" {
+		t.Errorf("email mutated on rejected login: %q", row.Email)
+	}
+	if row.DeactivatedAt == nil {
+		t.Error("deactivated_at was cleared on rejected login")
+	}
+}
+
+// TestService_HandleCallback_AllowsReactivatedUser covers the
+// Reactivate handler's wire end: after `users.deactivated_at` is
+// cleared, the next OIDC login goes through the update path
+// normally. Pins the inverse of TestService_HandleCallback_RejectsDeactivatedUser.
+func TestService_HandleCallback_AllowsReactivatedUser(t *testing.T) {
+	idp := newMockIdP(t)
+	users := newStubUsers()
+
+	prov := makeProvider(idp.URL(), "op-react")
+	seeded := &userdomain.User{
+		ID:                  "u-reactivated",
+		TenantID:            prov.TenantID,
+		Email:               "reactivated@example.com",
+		DisplayName:         "Reactivated User",
+		OIDCSubject:         "test-subject",
+		OIDCProviderID:      "op-react",
+		LastLoginAt:         time.Now().UTC().Add(-2 * time.Hour),
+		WebAuthnCredentials: []byte("[]"),
+		CreatedAt:           time.Now().UTC().Add(-24 * time.Hour),
+		UpdatedAt:           time.Now().UTC().Add(-1 * time.Hour),
+		DeactivatedAt:       nil, // active again
+	}
+	users.byID[seeded.ID] = seeded
+	users.bySubject["op-react:test-subject"] = seeded
+
+	pl := newStubPreLogin()
+	mappings := &stubMappings{roleIDs: []string{"r-operator"}}
+	sessions := &stubSessions{}
+	svc := NewService(&stubProviderLookup{provider: prov}, mappings, users, sessions, pl, "")
+
+	cookie, _, _ := pl.CreatePreLogin(context.Background(), "op-react", "react-state", "test-nonce-fixed",
+		"v-reactiveeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee", "", "")
+	res, err := svc.HandleCallback(context.Background(), cookie, "code", "react-state", "", "10.0.0.1", "Mozilla/5.0")
+	if err != nil {
+		t.Fatalf("HandleCallback after reactivation: %v", err)
+	}
+	if res == nil || res.User == nil {
+		t.Fatal("expected non-nil callback result after reactivation")
+	}
+	if res.User.ID != "u-reactivated" {
+		t.Errorf("CallbackResult.User.ID = %q; want u-reactivated", res.User.ID)
+	}
+}
+
+// TestService_HandleCallback_DeactivatedUserPreservesForensics
+// makes the defense-in-depth claim explicit: a rejected login does
+// not bump last_login_at. This guards against a regression where
+// someone "fixes" upsertUser by re-ordering the assignments to set
+// LastLoginAt before checking DeactivatedAt.
+func TestService_HandleCallback_DeactivatedUserPreservesForensics(t *testing.T) {
+	idp := newMockIdP(t)
+	users := newStubUsers()
+
+	deactivatedAt := time.Now().UTC().Add(-30 * time.Minute)
+	prov := makeProvider(idp.URL(), "op-forensic")
+	seeded := &userdomain.User{
+		ID:                  "u-forensic",
+		TenantID:            prov.TenantID,
+		Email:               "forensic@example.com",
+		DisplayName:         "Forensic User",
+		OIDCSubject:         "test-subject",
+		OIDCProviderID:      "op-forensic",
+		LastLoginAt:         time.Now().UTC().Add(-48 * time.Hour),
+		WebAuthnCredentials: []byte("[]"),
+		CreatedAt:           time.Now().UTC().Add(-72 * time.Hour),
+		UpdatedAt:           time.Now().UTC().Add(-30 * time.Minute),
+		DeactivatedAt:       &deactivatedAt,
+	}
+	users.byID[seeded.ID] = seeded
+	users.bySubject["op-forensic:test-subject"] = seeded
+	frozenLastLogin := seeded.LastLoginAt
+
+	pl := newStubPreLogin()
+	mappings := &stubMappings{roleIDs: []string{"r-operator"}}
+	sessions := &stubSessions{}
+	svc := NewService(&stubProviderLookup{provider: prov}, mappings, users, sessions, pl, "")
+
+	cookie, _, _ := pl.CreatePreLogin(context.Background(), "op-forensic", "for-state", "test-nonce-fixed",
+		"v-forensiccccccccccccccccccccccccccccccccc", "", "")
+	_, err := svc.HandleCallback(context.Background(), cookie, "code", "for-state", "", "10.0.0.1", "Mozilla/5.0")
+	if !errors.Is(err, ErrUserDeactivated) {
+		t.Fatalf("err = %v; want ErrUserDeactivated", err)
+	}
+
+	row := users.byID["u-forensic"]
+	if row.LastLoginAt != frozenLastLogin {
+		t.Errorf("last_login_at advanced on rejected login (forensics tainted): %v -> %v",
+			frozenLastLogin, row.LastLoginAt)
+	}
+}
+
 // TestService_ATHash_CoversAllAllowedAlgs pins the at_hash alg dispatch
 // for every algorithm in DefaultAllowedAlgs.
 func TestService_ATHash_CoversAllAllowedAlgs(t *testing.T) {

internal/repository/postgres/user.go

@@ -23,19 +23,33 @@ func NewUserRepository(db *sql.DB) *UserRepository {
 	return &UserRepository{db: db}
 }
 
+// Audit 2026-05-11 A-2 — deactivated_at column added in migration
+// 000045 (MED-11 foundation) but pre-fix never read here. The
+// federated-user soft-delete flow at
+// internal/api/handler/auth_users.go::Deactivate set the column on
+// Update, but Get / GetByOIDCSubject / ListAll all returned User
+// with zero-value DeactivatedAt regardless. The OIDC login path
+// trusts the returned struct, so a deactivated user's next login
+// re-elevated them. Adding the column to userColumns + scanUser
+// closes the read leg; service.go's upsertUser closes the enforce leg.
 const userColumns = `id, tenant_id, email, display_name, oidc_subject,
 		oidc_provider_id, last_login_at, webauthn_credentials,
-		created_at, updated_at`
+		created_at, updated_at, deactivated_at`
 
 func scanUser(row interface{ Scan(...interface{}) error }) (*userdomain.User, error) {
 	var u userdomain.User
+	var deactivatedAt sql.NullTime
 	if err := row.Scan(
 		&u.ID, &u.TenantID, &u.Email, &u.DisplayName, &u.OIDCSubject,
 		&u.OIDCProviderID, &u.LastLoginAt, &u.WebAuthnCredentials,
-		&u.CreatedAt, &u.UpdatedAt,
+		&u.CreatedAt, &u.UpdatedAt, &deactivatedAt,
 	); err != nil {
 		return nil, err
 	}
+	if deactivatedAt.Valid {
+		t := deactivatedAt.Time
+		u.DeactivatedAt = &t
+	}
 	return &u, nil
 }
 
@@ -74,14 +88,26 @@ func (r *UserRepository) GetByOIDCSubject(ctx context.Context, providerID, subje
 // Create persists a new user. Translates SQLSTATE 23505 into
 // ErrUserDuplicateOIDCSubject (the unique constraint on
 // (oidc_provider_id, oidc_subject)).
+//
+// Audit 2026-05-11 A-2 — deactivated_at written explicitly. New rows
+// pre-fix had deactivated_at NULL by schema default; the explicit
+// write makes forward-compat with future seed-data paths that
+// pre-populate the column (e.g. migration of an external user roster
+// where some entries land deactivated). nil → NULL via sql.NullTime.
 func (r *UserRepository) Create(ctx context.Context, u *userdomain.User) error {
+	var deactivatedAt sql.NullTime
+	if u.DeactivatedAt != nil {
+		deactivatedAt = sql.NullTime{Time: *u.DeactivatedAt, Valid: true}
+	}
 	_, err := r.db.ExecContext(ctx, `
 		INSERT INTO users (
 			id, tenant_id, email, display_name, oidc_subject,
-			oidc_provider_id, last_login_at, webauthn_credentials
-		) VALUES ($1, $2, $3, $4, $5, $6, $7, $8)`,
+			oidc_provider_id, last_login_at, webauthn_credentials,
+			deactivated_at
+		) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)`,
 		u.ID, u.TenantID, u.Email, u.DisplayName, u.OIDCSubject,
-		u.OIDCProviderID, u.LastLoginAt, u.WebAuthnCredentials)
+		u.OIDCProviderID, u.LastLoginAt, u.WebAuthnCredentials,
+		deactivatedAt)
 	if err != nil {
 		var pqErr *pq.Error
 		if errors.As(err, &pqErr) && pqErr.Code == "23505" {
@@ -93,18 +119,31 @@ func (r *UserRepository) Create(ctx context.Context, u *userdomain.User) error {
 }
 
 // Update writes the mutable fields (email, display_name, last_login_at,
-// webauthn_credentials) back to the row. Immutable: id, tenant_id,
-// oidc_subject, oidc_provider_id, created_at. updated_at = NOW().
+// webauthn_credentials, deactivated_at) back to the row. Immutable:
+// id, tenant_id, oidc_subject, oidc_provider_id, created_at.
+// updated_at = NOW().
+//
+// Audit 2026-05-11 A-2 — deactivated_at is now in the mutable set so
+// the federated-user soft-delete flow at
+// internal/api/handler/auth_users.go::Deactivate persists. Pre-fix the
+// Update SQL omitted it; the handler set u.DeactivatedAt = now on the
+// in-memory struct, called Update, the SQL ignored the field, and the
+// row was unchanged. nil DeactivatedAt → NULL (supports reactivation).
 func (r *UserRepository) Update(ctx context.Context, u *userdomain.User) error {
+	var deactivatedAt sql.NullTime
+	if u.DeactivatedAt != nil {
+		deactivatedAt = sql.NullTime{Time: *u.DeactivatedAt, Valid: true}
+	}
 	res, err := r.db.ExecContext(ctx, `
 		UPDATE users SET
 			email = $2,
 			display_name = $3,
 			last_login_at = $4,
 			webauthn_credentials = $5,
+			deactivated_at = $6,
 			updated_at = NOW()
 		WHERE id = $1`,
-		u.ID, u.Email, u.DisplayName, u.LastLoginAt, u.WebAuthnCredentials)
+		u.ID, u.Email, u.DisplayName, u.LastLoginAt, u.WebAuthnCredentials, deactivatedAt)
 	if err != nil {
 		return fmt.Errorf("users update: %w", err)
 	}

internal/repository/postgres/user_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"testing"
+	"time"
 
 	userdomain "github.com/certctl-io/certctl/internal/auth/user/domain"
 	"github.com/certctl-io/certctl/internal/repository"
@@ -193,6 +194,178 @@ func TestUserRepository_ListAll(t *testing.T) {
 	}
 }
 
+// TestUserRepository_DeactivatedAt_RoundTrip pins the A-2 closure at
+// the SQL layer. Pre-fix scanUser did not include deactivated_at in
+// userColumns, Update did not write it, and Create did not write it.
+// Result: a non-nil DeactivatedAt set in the in-memory User by the
+// handler was lost on persist + always nil on read. This test
+// exercises both legs.
+//
+// Audit 2026-05-11 A-2 — round-trip a non-nil DeactivatedAt through
+// Update and verify Get + GetByOIDCSubject + ListAll all return it
+// non-nil. Then clear it (reactivate path) and verify the nil
+// round-trips back.
+func TestUserRepository_DeactivatedAt_RoundTrip(t *testing.T) {
+	if testing.Short() {
+		t.Skip("integration test in short mode")
+	}
+	db := getTestDB(t).freshSchema(t)
+	providerRepo := postgres.NewOIDCProviderRepository(db)
+	userRepo := postgres.NewUserRepository(db)
+	ctx := context.Background()
+
+	p := newValidProvider("deact-rt")
+	if err := providerRepo.Create(ctx, p); err != nil {
+		t.Fatalf("Create provider: %v", err)
+	}
+	u := newValidUser("deactivated-user", p.ID)
+	if err := userRepo.Create(ctx, u); err != nil {
+		t.Fatalf("Create user: %v", err)
+	}
+
+	// Sanity: a freshly-created row reads back nil.
+	got, err := userRepo.Get(ctx, u.ID)
+	if err != nil {
+		t.Fatalf("Get (fresh): %v", err)
+	}
+	if got.DeactivatedAt != nil {
+		t.Errorf("freshly-created user has non-nil DeactivatedAt: %v", got.DeactivatedAt)
+	}
+
+	// Soft-delete: set DeactivatedAt and Update.
+	now := time.Now().UTC().Truncate(time.Microsecond) // pg precision
+	got.DeactivatedAt = &now
+	if err := userRepo.Update(ctx, got); err != nil {
+		t.Fatalf("Update (deactivate): %v", err)
+	}
+
+	// Read via Get.
+	rb, err := userRepo.Get(ctx, u.ID)
+	if err != nil {
+		t.Fatalf("Get (post-deactivate): %v", err)
+	}
+	if rb.DeactivatedAt == nil {
+		t.Fatal("Get returned nil DeactivatedAt after Update set it (A-2 regression)")
+	}
+	if !rb.DeactivatedAt.Equal(now) {
+		t.Errorf("Get round-trip DeactivatedAt mismatch: got %v want %v", *rb.DeactivatedAt, now)
+	}
+
+	// Read via GetByOIDCSubject.
+	rs, err := userRepo.GetByOIDCSubject(ctx, p.ID, u.OIDCSubject)
+	if err != nil {
+		t.Fatalf("GetByOIDCSubject (post-deactivate): %v", err)
+	}
+	if rs.DeactivatedAt == nil {
+		t.Error("GetByOIDCSubject returned nil DeactivatedAt after Update set it (A-2 regression — OIDC login path leak)")
+	}
+
+	// Read via ListAll.
+	rows, err := userRepo.ListAll(ctx, "t-default")
+	if err != nil {
+		t.Fatalf("ListAll: %v", err)
+	}
+	if len(rows) != 1 || rows[0].DeactivatedAt == nil {
+		t.Errorf("ListAll: expected 1 row with non-nil DeactivatedAt; got %d rows, first DeactivatedAt=%v",
+			len(rows), func() interface{} {
+				if len(rows) == 0 {
+					return "no rows"
+				}
+				return rows[0].DeactivatedAt
+			}())
+	}
+
+	// Reactivate: clear DeactivatedAt and verify the nil round-trips.
+	rb.DeactivatedAt = nil
+	if err := userRepo.Update(ctx, rb); err != nil {
+		t.Fatalf("Update (reactivate): %v", err)
+	}
+	rfin, err := userRepo.Get(ctx, u.ID)
+	if err != nil {
+		t.Fatalf("Get (post-reactivate): %v", err)
+	}
+	if rfin.DeactivatedAt != nil {
+		t.Errorf("Get returned non-nil DeactivatedAt after reactivate Update cleared it: %v", *rfin.DeactivatedAt)
+	}
+}
+
+// TestUserRepository_DeactivatedAt_CreateWritesNullForActive pins
+// the Create path's behavior for the common case (active user).
+// Pre-fix Create omitted deactivated_at entirely so the column took
+// the schema default (NULL). Now Create writes it explicitly; the
+// observable behavior is unchanged for nil, but a regression would
+// flip new users to deactivated.
+//
+// Audit 2026-05-11 A-2.
+func TestUserRepository_DeactivatedAt_CreateWritesNullForActive(t *testing.T) {
+	if testing.Short() {
+		t.Skip("integration test in short mode")
+	}
+	db := getTestDB(t).freshSchema(t)
+	providerRepo := postgres.NewOIDCProviderRepository(db)
+	userRepo := postgres.NewUserRepository(db)
+	ctx := context.Background()
+
+	p := newValidProvider("create-nil")
+	if err := providerRepo.Create(ctx, p); err != nil {
+		t.Fatalf("Create provider: %v", err)
+	}
+	u := newValidUser("active-user", p.ID)
+	u.DeactivatedAt = nil // explicit: new user is active
+	if err := userRepo.Create(ctx, u); err != nil {
+		t.Fatalf("Create: %v", err)
+	}
+
+	got, err := userRepo.Get(ctx, u.ID)
+	if err != nil {
+		t.Fatalf("Get: %v", err)
+	}
+	if got.DeactivatedAt != nil {
+		t.Errorf("active user has non-nil DeactivatedAt after Create: %v", *got.DeactivatedAt)
+	}
+}
+
+// TestUserRepository_DeactivatedAt_CreatePersistsPreDeactivated
+// covers the forward-compat path where a future seed-data flow
+// (e.g. migration of an external user roster where some entries
+// land deactivated) pre-populates the column on insert. Pre-fix
+// Create omitted the column entirely, so this case wasn't
+// representable; the A-2 closure makes the explicit write part of
+// the Create contract.
+//
+// Audit 2026-05-11 A-2.
+func TestUserRepository_DeactivatedAt_CreatePersistsPreDeactivated(t *testing.T) {
+	if testing.Short() {
+		t.Skip("integration test in short mode")
+	}
+	db := getTestDB(t).freshSchema(t)
+	providerRepo := postgres.NewOIDCProviderRepository(db)
+	userRepo := postgres.NewUserRepository(db)
+	ctx := context.Background()
+
+	p := newValidProvider("create-deact")
+	if err := providerRepo.Create(ctx, p); err != nil {
+		t.Fatalf("Create provider: %v", err)
+	}
+	u := newValidUser("seed-deactivated", p.ID)
+	pre := time.Now().UTC().Add(-1 * time.Hour).Truncate(time.Microsecond)
+	u.DeactivatedAt = &pre
+	if err := userRepo.Create(ctx, u); err != nil {
+		t.Fatalf("Create: %v", err)
+	}
+
+	got, err := userRepo.Get(ctx, u.ID)
+	if err != nil {
+		t.Fatalf("Get: %v", err)
+	}
+	if got.DeactivatedAt == nil {
+		t.Fatal("DeactivatedAt nil after Create persisted a pre-deactivated user")
+	}
+	if !got.DeactivatedAt.Equal(pre) {
+		t.Errorf("Create round-trip DeactivatedAt: got %v want %v", *got.DeactivatedAt, pre)
+	}
+}
+
 // TestUserRepository_DeletingProviderRefusedWhenUsersReference complements
 // the OIDCProviderRepository test of the same shape; pinning both ends
 // of the FK ON DELETE RESTRICT contract.

web/src/api/client.ts

@@ -341,6 +341,10 @@ export const authListUsers = (providerID?: string) => {
 };
 export const authDeactivateUser = (id: string) =>
   fetchJSON<unknown>(`${BASE}/auth/users/${id}`, { method: 'DELETE' });
+// Audit 2026-05-11 A-2 — inverse of authDeactivateUser. Clears
+// users.deactivated_at; next OIDC login proceeds normally.
+export const authReactivateUser = (id: string) =>
+  fetchJSON<unknown>(`${BASE}/auth/users/${id}/reactivate`, { method: 'POST' });
 
 // MED-12 — runtime config.
 export const authRuntimeConfig = () =>

web/src/pages/auth/UsersPage.tsx

@@ -1,6 +1,6 @@
 import { useState } from 'react';
 import { useQuery, useQueryClient } from '@tanstack/react-query';
-import { authListUsers, authDeactivateUser, type AuthUser } from '../../api/client';
+import { authListUsers, authDeactivateUser, authReactivateUser, type AuthUser } from '../../api/client';
 import PageHeader from '../../components/PageHeader';
 import ErrorState from '../../components/ErrorState';
 
@@ -47,6 +47,29 @@ export default function UsersPage() {
     }
   }
 
+  // Audit 2026-05-11 A-2 — Reactivate inverse. Clears deactivated_at;
+  // the next OIDC login under the same (provider, subject) tuple
+  // proceeds normally. Sessions revoked at deactivation stay revoked
+  // (the cascade is irreversible by design — the user must complete
+  // a fresh login).
+  async function reactivate(u: AuthUser) {
+    if (!confirm(`Reactivate user ${u.email} (${u.id})?\n\n` +
+      `This clears deactivated_at. The user can OIDC-login again. ` +
+      `Previously-revoked sessions stay revoked.`)) {
+      return;
+    }
+    setPending(u.id);
+    setErr(null);
+    try {
+      await authReactivateUser(u.id);
+      await qc.invalidateQueries({ queryKey: ['auth', 'users'] });
+    } catch (e) {
+      setErr(e instanceof Error ? e.message : String(e));
+    } finally {
+      setPending(null);
+    }
+  }
+
   return (
     <div>
       <PageHeader title="Federated Users" subtitle="One row per (oidc_provider_id, oidc_subject) tuple." />
@@ -97,6 +120,15 @@ export default function UsersPage() {
                         {pending === u.id ? 'Deactivating…' : 'Deactivate'}
                       </button>
                     )}
+                    {deactivated && (
+                      <button
+                        onClick={() => reactivate(u)}
+                        disabled={pending === u.id}
+                        style={{ padding: '4px 12px' }}
+                      >
+                        {pending === u.id ? 'Reactivating…' : 'Reactivate'}
+                      </button>
+                    )}
                   </td>
                 </tr>
               );