diff --git a/app/Modules/Files/Http/Controllers/ChunkedUploadsController.php b/app/Modules/Files/Http/Controllers/ChunkedUploadsController.php
index a72d81bc..0aa71e28 100644
--- a/app/Modules/Files/Http/Controllers/ChunkedUploadsController.php
+++ b/app/Modules/Files/Http/Controllers/ChunkedUploadsController.php
@@ -250,6 +250,22 @@ class ChunkedUploadsController extends Controller
             throw ValidationException::withMessages(['parts' => $exception->getMessage()]);
         }
 
+        // store()'s size check ran against the client-declared, unverified
+        // size, so a small declared size would otherwise let an upload of any
+        // size through here. Re-check the real assembled byte count against
+        // the same limit store() applies to everyone. No File row exists yet
+        // at this point, so cleanup only needs to undo what assemble() wrote.
+        $maxMb = (int) $this->settings->get(Setting::MaxFileSizeMb);
+
+        if ($maxMb > 0 && $assembled['size'] > $maxMb * 1024 * 1024) {
+            Storage::disk($assembled['disk'])->delete($assembled['path']);
+            $session->delete();
+
+            throw ValidationException::withMessages([
+                'size' => __('This file exceeds the maximum allowed size of :max MB.', ['max' => (string) $maxMb]),
+            ]);
+        }
+
         // store()'s quota check used a client-declared, unverified size —
         // re-check against the real assembled byte count before this
         // becomes a File row. No File row exists yet at this point, so
diff --git a/tests/Feature/Files/ChunkedUploadsTest.php b/tests/Feature/Files/ChunkedUploadsTest.php
index 4b672500..bfbcc041 100644
--- a/tests/Feature/Files/ChunkedUploadsTest.php
+++ b/tests/Feature/Files/ChunkedUploadsTest.php
@@ -163,6 +163,41 @@ test('a staff account without the upload permission cannot create sessions', fun
     $this->postJson('/uploads', ['filename' => 'x.zip', 'size' => 10])->assertForbidden();
 });
 
+test('complete refuses a file whose real assembled size exceeds the limit, even when a tiny size was declared', function () {
+    $this->actingAs($this->admin);
+
+    // A 1 MB cap. The session is declared as a single byte, so it sails
+    // through store()'s check against the client-supplied size.
+    app(Settings::class)->set(Setting::MaxFileSizeMb, 1);
+    $sessionId = createSession(1, 'sneaky.zip');
+
+    // But the real parts stream ~1.5 MB.
+    $chunk = str_repeat('a', 800 * 1024);
+    putPart($sessionId, 1, $chunk)->assertOk();
+    putPart($sessionId, 2, $chunk)->assertOk();
+
+    $this->postJson("/uploads/{$sessionId}/complete")->assertStatus(422);
+
+    // Nothing is kept: no File row, the assembled bytes are removed, and the
+    // session is gone.
+    expect(File::query()->count())->toBe(0)
+        ->and(UploadSession::query()->find($sessionId))->toBeNull()
+        ->and(Storage::disk('files')->allFiles())->toBe([]);
+});
+
+test('complete still accepts a file at exactly the limit', function () {
+    $this->actingAs($this->admin);
+
+    app(Settings::class)->set(Setting::MaxFileSizeMb, 1);
+    $sessionId = createSession(1024 * 1024, 'exact.zip');
+
+    putPart($sessionId, 1, str_repeat('a', 1024 * 1024))->assertOk();
+
+    $response = $this->postJson("/uploads/{$sessionId}/complete")->assertOk();
+
+    expect(File::query()->findOrFail($response->json('file_id'))->size)->toBe(1024 * 1024);
+});
+
 test('a client with the upload permission can create a session and complete an upload', function () {
     $client = User::factory()->client()->create();
     grantChunkedUploadPermission($client);