diff --git a/crates/credentials/src/credentials.rs b/crates/credentials/src/credentials.rs
index c06024115..b8d256f78 100644
--- a/crates/credentials/src/credentials.rs
+++ b/crates/credentials/src/credentials.rs
@@ -29,6 +29,12 @@ static GLOBAL_ACTIVE_CRED: OnceLock<Credentials> = OnceLock::new();
 /// Global RPC authentication token
 pub static GLOBAL_RUSTFS_RPC_SECRET: OnceLock<String> = OnceLock::new();
 
+/// Public error returned when RPC authentication is not safely configured.
+pub const RPC_SECRET_REQUIRED_MESSAGE: &str = "RPC authentication secret is not configured";
+
+/// Operator-facing guidance for configuring RPC authentication safely.
+pub const RPC_SECRET_REQUIRED_OPERATOR_MESSAGE: &str = "RUSTFS_RPC_SECRET must be set to a non-default value or RUSTFS_SECRET_KEY must be changed from the default for RPC authentication";
+
 /// Error type for credentials operations
 #[derive(Debug)]
 pub enum CredentialsError {
@@ -216,13 +222,39 @@ pub fn gen_secret_key(length: usize) -> std::io::Result<String> {
 /// # Returns
 /// * `String` - The RPC authentication token
 ///
+fn resolve_rpc_secret(env_secret: Option<&str>, global_secret: Option<&str>) -> Option<String> {
+    if let Some(secret) = env_secret.map(str::trim).filter(|secret| !secret.is_empty()) {
+        return (secret != DEFAULT_SECRET_KEY).then(|| secret.to_string());
+    }
+
+    global_secret
+        .map(str::trim)
+        .filter(|secret| !secret.is_empty() && *secret != DEFAULT_SECRET_KEY)
+        .map(ToOwned::to_owned)
+}
+
+pub fn try_get_rpc_token() -> std::io::Result<String> {
+    if let Some(secret) = GLOBAL_RUSTFS_RPC_SECRET.get() {
+        return resolve_rpc_secret(None, Some(secret)).ok_or_else(|| Error::other(RPC_SECRET_REQUIRED_MESSAGE));
+    }
+
+    let env_secret = env::var(ENV_RPC_SECRET).ok();
+    let global_secret = get_global_secret_key_opt();
+    let secret = resolve_rpc_secret(env_secret.as_deref(), global_secret.as_deref())
+        .ok_or_else(|| Error::other(RPC_SECRET_REQUIRED_MESSAGE))?;
+
+    match GLOBAL_RUSTFS_RPC_SECRET.set(secret.clone()) {
+        Ok(()) => Ok(secret),
+        Err(_) => GLOBAL_RUSTFS_RPC_SECRET
+            .get()
+            .and_then(|stored| resolve_rpc_secret(None, Some(stored)))
+            .ok_or_else(|| Error::other(RPC_SECRET_REQUIRED_MESSAGE)),
+    }
+}
+
+#[deprecated(note = "use try_get_rpc_token to handle missing RPC secrets explicitly")]
 pub fn get_rpc_token() -> String {
-    GLOBAL_RUSTFS_RPC_SECRET
-        .get_or_init(|| {
-            env::var(ENV_RPC_SECRET)
-                .unwrap_or_else(|_| get_global_secret_key_opt().unwrap_or_else(|| DEFAULT_SECRET_KEY.to_string()))
-        })
-        .clone()
+    try_get_rpc_token().expect(RPC_SECRET_REQUIRED_MESSAGE)
 }
 
 /// A wrapper struct for masking sensitive strings in Debug implementations.
@@ -301,7 +333,7 @@ impl fmt::Debug for Credentials {
         f.debug_struct("Credentials")
             .field("access_key", &self.access_key)
             .field("secret_key", &Masked(Some(&self.secret_key)))
-            .field("session_token", &self.session_token)
+            .field("session_token", &Masked(Some(&self.session_token)))
             .field("expiration", &self.expiration)
             .field("status", &self.status)
             .field("parent_user", &self.parent_user)
@@ -495,6 +527,37 @@ mod tests {
         assert!(!key.contains('='));
     }
 
+    #[test]
+    fn test_resolve_rpc_secret_rejects_default_fallback() {
+        assert!(resolve_rpc_secret(None, None).is_none());
+        assert!(resolve_rpc_secret(None, Some(DEFAULT_SECRET_KEY)).is_none());
+        assert!(resolve_rpc_secret(Some(DEFAULT_SECRET_KEY), Some("custom-global-secret")).is_none());
+    }
+
+    #[test]
+    fn test_rpc_secret_public_error_omits_configuration_details() {
+        assert!(!RPC_SECRET_REQUIRED_MESSAGE.contains("RUSTFS_"));
+        assert!(!RPC_SECRET_REQUIRED_MESSAGE.contains(DEFAULT_SECRET_KEY));
+        assert!(RPC_SECRET_REQUIRED_OPERATOR_MESSAGE.contains("RUSTFS_RPC_SECRET"));
+    }
+
+    #[allow(deprecated)]
+    #[test]
+    fn test_get_rpc_token_preserves_string_return_type() {
+        fn assert_string_return(_: fn() -> String) {}
+
+        assert_string_return(get_rpc_token);
+    }
+
+    #[test]
+    fn test_resolve_rpc_secret_accepts_non_default_secret() {
+        assert_eq!(resolve_rpc_secret(Some("custom-rpc-secret"), None).as_deref(), Some("custom-rpc-secret"));
+        assert_eq!(
+            resolve_rpc_secret(None, Some("custom-global-secret")).as_deref(),
+            Some("custom-global-secret")
+        );
+    }
+
     #[test]
     fn test_masked_debug() {
         // Test None
@@ -524,6 +587,24 @@ mod tests {
         assert_eq!(format!("{:?}", Masked(Some("中文测试"))), "中***试|4");
     }
 
+    #[test]
+    fn test_credentials_debug_masks_sensitive_fields() {
+        let cred = Credentials {
+            access_key: "debug-access-key".to_string(),
+            secret_key: "debug-secret-key".to_string(),
+            session_token: "debug-session-token".to_string(),
+            parent_user: "parent-user".to_string(),
+            ..Default::default()
+        };
+
+        let output = format!("{cred:?}");
+
+        assert!(output.contains("debug-access-key"));
+        assert!(output.contains("parent-user"));
+        assert!(!output.contains("debug-secret-key"));
+        assert!(!output.contains("debug-session-token"));
+    }
+
     #[test]
     fn test_credentials_expiration_serialize_as_rfc3339() {
         use time::OffsetDateTime;
diff --git a/crates/ecstore/src/rpc/client.rs b/crates/ecstore/src/rpc/client.rs
index 43a1c37f0..2138345b6 100644
--- a/crates/ecstore/src/rpc/client.rs
+++ b/crates/ecstore/src/rpc/client.rs
@@ -96,7 +96,8 @@ pub struct TonicSignatureInterceptor;
 
 impl tonic::service::Interceptor for TonicSignatureInterceptor {
     fn call(&mut self, mut req: tonic::Request<()>) -> Result<tonic::Request<()>, tonic::Status> {
-        let headers = gen_signature_headers(TONIC_RPC_PREFIX, &Method::GET);
+        let headers = gen_signature_headers(TONIC_RPC_PREFIX, &Method::GET)
+            .map_err(|_| tonic::Status::unauthenticated("No valid auth token"))?;
         req.metadata_mut().as_mut().extend(headers);
         inject_trace_context_into_metadata(req.metadata_mut());
         inject_request_id_into_metadata(req.metadata_mut());
@@ -135,8 +136,13 @@ mod tests {
     use super::*;
     use tonic::service::Interceptor;
 
+    fn ensure_test_rpc_secret() {
+        let _ = rustfs_credentials::GLOBAL_RUSTFS_RPC_SECRET.set("test-rpc-secret".to_string());
+    }
+
     #[test]
     fn test_signature_interceptor_keeps_auth_headers() {
+        ensure_test_rpc_secret();
         let mut interceptor = TonicSignatureInterceptor;
         let req = tonic::Request::new(());
 
@@ -148,6 +154,7 @@ mod tests {
 
     #[test]
     fn test_signature_interceptor_may_inject_request_id() {
+        ensure_test_rpc_secret();
         let mut interceptor = TonicSignatureInterceptor;
         let req = tonic::Request::new(());
 
diff --git a/crates/ecstore/src/rpc/http_auth.rs b/crates/ecstore/src/rpc/http_auth.rs
index 9f267d248..c494b54c7 100644
--- a/crates/ecstore/src/rpc/http_auth.rs
+++ b/crates/ecstore/src/rpc/http_auth.rs
@@ -17,8 +17,11 @@ use base64::Engine as _;
 use base64::engine::general_purpose;
 use hmac::{Hmac, KeyInit, Mac};
 use http::{HeaderMap, HeaderValue, Method, Uri};
-use rustfs_credentials::{DEFAULT_SECRET_KEY, ENV_RPC_SECRET, get_global_secret_key_opt};
+#[cfg(test)]
+use rustfs_credentials::{DEFAULT_SECRET_KEY, RPC_SECRET_REQUIRED_MESSAGE};
+use rustfs_credentials::{RPC_SECRET_REQUIRED_OPERATOR_MESSAGE, try_get_rpc_token};
 use sha2::Sha256;
+use std::sync::Once;
 use time::OffsetDateTime;
 use tracing::error;
 
@@ -28,19 +31,31 @@ const SIGNATURE_HEADER: &str = "x-rustfs-signature";
 const TIMESTAMP_HEADER: &str = "x-rustfs-timestamp";
 const SIGNATURE_VALID_DURATION: i64 = 300; // 5 minutes
 pub const TONIC_RPC_PREFIX: &str = "/node_service.NodeService";
+static RPC_SECRET_RESOLUTION_LOG_ONCE: Once = Once::new();
 
 /// Get the shared secret for HMAC signing
-fn get_shared_secret() -> String {
-    rustfs_credentials::GLOBAL_RUSTFS_RPC_SECRET
-        .get_or_init(|| {
-            rustfs_utils::get_env_str(
-                ENV_RPC_SECRET,
-                get_global_secret_key_opt()
-                    .unwrap_or_else(|| DEFAULT_SECRET_KEY.to_string())
-                    .as_str(),
-            )
-        })
-        .clone()
+#[cfg(test)]
+fn resolve_shared_secret(env_secret: Option<&str>, global_secret: Option<&str>) -> std::io::Result<String> {
+    if let Some(secret) = env_secret.map(str::trim).filter(|secret| !secret.is_empty()) {
+        return (secret != DEFAULT_SECRET_KEY)
+            .then(|| secret.to_string())
+            .ok_or_else(|| std::io::Error::other(RPC_SECRET_REQUIRED_MESSAGE));
+    }
+
+    global_secret
+        .map(str::trim)
+        .filter(|secret| !secret.is_empty() && *secret != DEFAULT_SECRET_KEY)
+        .map(ToOwned::to_owned)
+        .ok_or_else(|| std::io::Error::other(RPC_SECRET_REQUIRED_MESSAGE))
+}
+
+fn get_shared_secret() -> std::io::Result<String> {
+    try_get_rpc_token().map_err(|err| {
+        RPC_SECRET_RESOLUTION_LOG_ONCE.call_once(|| {
+            error!("RPC auth secret resolution failed: {}; {}", err, RPC_SECRET_REQUIRED_OPERATOR_MESSAGE);
+        });
+        err
+    })
 }
 
 /// Generate HMAC-SHA256 signature for the given data
@@ -59,16 +74,17 @@ fn generate_signature(secret: &str, url: &str, method: &Method, timestamp: i64)
 }
 
 /// Build headers with authentication signature
-pub fn build_auth_headers(url: &str, method: &Method, headers: &mut HeaderMap) {
-    let auth_headers = gen_signature_headers(url, method);
+pub fn build_auth_headers(url: &str, method: &Method, headers: &mut HeaderMap) -> std::io::Result<()> {
+    let auth_headers = gen_signature_headers(url, method)?;
 
     headers.extend(auth_headers);
     inject_trace_context_into_http_headers(headers);
     inject_request_id_into_http_headers(headers);
+    Ok(())
 }
 
-pub fn gen_signature_headers(url: &str, method: &Method) -> HeaderMap {
-    let secret = get_shared_secret();
+pub fn gen_signature_headers(url: &str, method: &Method) -> std::io::Result<HeaderMap> {
+    let secret = get_shared_secret()?;
     let timestamp = OffsetDateTime::now_utc().unix_timestamp();
 
     let signature = generate_signature(&secret, url, method, timestamp);
@@ -80,13 +96,11 @@ pub fn gen_signature_headers(url: &str, method: &Method) -> HeaderMap {
         HeaderValue::from_str(&timestamp.to_string()).expect("Invalid header value"),
     );
 
-    headers
+    Ok(headers)
 }
 
 /// Verify the request signature for RPC requests
 pub fn verify_rpc_signature(url: &str, method: &Method, headers: &HeaderMap) -> std::io::Result<()> {
-    let secret = get_shared_secret();
-
     // Get signature from header
     let signature = headers
         .get(SIGNATURE_HEADER)
@@ -106,24 +120,24 @@ pub fn verify_rpc_signature(url: &str, method: &Method, headers: &HeaderMap) ->
     // Check timestamp validity (prevent replay attacks)
     let current_time = OffsetDateTime::now_utc().unix_timestamp();
 
-    if current_time.saturating_sub(timestamp) > SIGNATURE_VALID_DURATION {
+    if current_time.saturating_sub(timestamp) > SIGNATURE_VALID_DURATION
+        || timestamp.saturating_sub(current_time) > SIGNATURE_VALID_DURATION
+    {
         return Err(std::io::Error::other("Request timestamp expired"));
     }
 
     // Generate expected signature
+    let secret = get_shared_secret()?;
     let expected_signature = generate_signature(&secret, url, method, timestamp);
 
     // Compare signatures
     if signature != expected_signature {
         error!(
-            "verify_rpc_signature: Invalid signature: url {}, method {}, timestamp {}, signature {}, expected_signature: {}***{}|{}",
+            "verify_rpc_signature: Invalid signature: url {}, method {}, timestamp {}, signature_len {}",
             url,
             method,
             timestamp,
-            signature,
-            expected_signature.chars().next().unwrap_or('*'),
-            expected_signature.chars().last().unwrap_or('*'),
-            expected_signature.len()
+            signature.len()
         );
 
         return Err(std::io::Error::other("Invalid signature"));
@@ -137,18 +151,79 @@ mod tests {
     use super::*;
     use crate::rpc::context_propagation::REQUEST_ID_HEADER;
     use http::{HeaderMap, Method};
+    use std::io::{self, Write};
+    use std::sync::{Arc, Mutex};
     use time::OffsetDateTime;
+    use tracing_subscriber::fmt::MakeWriter;
+
+    #[derive(Clone, Default)]
+    struct CapturedLogs {
+        buffer: Arc<Mutex<Vec<u8>>>,
+    }
+
+    struct CapturedLogWriter {
+        buffer: Arc<Mutex<Vec<u8>>>,
+    }
+
+    impl CapturedLogs {
+        fn contents(&self) -> String {
+            let buffer = self
+                .buffer
+                .lock()
+                .expect("captured logs mutex should not be poisoned")
+                .clone();
+            String::from_utf8(buffer).expect("captured logs should be valid UTF-8")
+        }
+    }
+
+    impl Write for CapturedLogWriter {
+        fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+            self.buffer
+                .lock()
+                .expect("captured logs mutex should not be poisoned")
+                .extend_from_slice(buf);
+            Ok(buf.len())
+        }
+
+        fn flush(&mut self) -> io::Result<()> {
+            Ok(())
+        }
+    }
+
+    impl<'a> MakeWriter<'a> for CapturedLogs {
+        type Writer = CapturedLogWriter;
+
+        fn make_writer(&'a self) -> Self::Writer {
+            CapturedLogWriter {
+                buffer: Arc::clone(&self.buffer),
+            }
+        }
+    }
+
+    fn ensure_test_rpc_secret() {
+        let _ = rustfs_credentials::GLOBAL_RUSTFS_RPC_SECRET.set("test-rpc-secret".to_string());
+    }
+
+    #[test]
+    fn test_resolve_shared_secret_rejects_default_fallback() {
+        let err = resolve_shared_secret(None, None).expect_err("default fallback must be rejected");
+        assert_eq!(err.to_string(), RPC_SECRET_REQUIRED_MESSAGE);
+
+        let err = resolve_shared_secret(None, Some(DEFAULT_SECRET_KEY)).expect_err("default global secret must be rejected");
+        assert_eq!(err.to_string(), RPC_SECRET_REQUIRED_MESSAGE);
+    }
 
     #[test]
     fn test_get_shared_secret() {
-        let secret = get_shared_secret();
+        ensure_test_rpc_secret();
+        let secret = get_shared_secret().expect("test RPC secret should resolve");
         assert!(!secret.is_empty(), "Secret should not be empty");
 
         let url = "http://node1:7000/rustfs/rpc/read_file_stream?disk=http%3A%2F%2Fnode1%3A7000%2Fdata%2Frustfs3&volume=.rustfs.sys&path=pool.bin%2Fdd0fd773-a962-4265-b543-783ce83953e9%2Fpart.1&offset=0&length=44";
         let method = Method::GET;
         let mut headers = HeaderMap::new();
 
-        build_auth_headers(url, &method, &mut headers);
+        build_auth_headers(url, &method, &mut headers).expect("auth headers should build");
 
         let url = "/rustfs/rpc/read_file_stream?disk=http%3A%2F%2Fnode1%3A7000%2Fdata%2Frustfs3&volume=.rustfs.sys&path=pool.bin%2Fdd0fd773-a962-4265-b543-783ce83953e9%2Fpart.1&offset=0&length=44";
 
@@ -189,11 +264,12 @@ mod tests {
 
     #[test]
     fn test_build_auth_headers() {
+        ensure_test_rpc_secret();
         let url = "http://example.com/api/test";
         let method = Method::POST;
         let mut headers = HeaderMap::new();
 
-        build_auth_headers(url, &method, &mut headers);
+        build_auth_headers(url, &method, &mut headers).expect("auth headers should build");
 
         // Verify headers are present
         assert!(headers.contains_key(SIGNATURE_HEADER), "Should contain signature header");
@@ -216,25 +292,27 @@ mod tests {
 
     #[test]
     fn test_build_auth_headers_preserves_existing_request_id() {
+        ensure_test_rpc_secret();
         let url = "http://example.com/api/test";
         let method = Method::GET;
         let mut headers = HeaderMap::new();
         headers.insert(REQUEST_ID_HEADER, HeaderValue::from_static("req-upstream-123"));
 
-        build_auth_headers(url, &method, &mut headers);
+        build_auth_headers(url, &method, &mut headers).expect("auth headers should build");
 
         assert_eq!(headers.get(REQUEST_ID_HEADER).and_then(|v| v.to_str().ok()), Some("req-upstream-123"));
     }
 
     #[test]
     fn test_build_auth_headers_may_set_request_id_from_trace_id() {
+        ensure_test_rpc_secret();
         let url = "http://example.com/api/test";
         let method = Method::GET;
         let mut headers = HeaderMap::new();
 
         let span = tracing::info_span!("rpc-test-span");
         let _guard = span.enter();
-        build_auth_headers(url, &method, &mut headers);
+        build_auth_headers(url, &method, &mut headers).expect("auth headers should build");
 
         if let Some(value) = headers.get(REQUEST_ID_HEADER).and_then(|v| v.to_str().ok()) {
             assert!(!value.is_empty(), "request id should not be empty");
@@ -243,12 +321,13 @@ mod tests {
 
     #[test]
     fn test_verify_rpc_signature_success() {
+        ensure_test_rpc_secret();
         let url = "http://example.com/api/test";
         let method = Method::GET;
         let mut headers = HeaderMap::new();
 
         // Build headers with valid signature
-        build_auth_headers(url, &method, &mut headers);
+        build_auth_headers(url, &method, &mut headers).expect("auth headers should build");
 
         // Verify should succeed
         let result = verify_rpc_signature(url, &method, &headers);
@@ -257,12 +336,13 @@ mod tests {
 
     #[test]
     fn test_verify_rpc_signature_invalid_signature() {
+        ensure_test_rpc_secret();
         let url = "http://example.com/api/test";
         let method = Method::GET;
         let mut headers = HeaderMap::new();
 
         // Build headers with valid signature first
-        build_auth_headers(url, &method, &mut headers);
+        build_auth_headers(url, &method, &mut headers).expect("auth headers should build");
 
         // Tamper with the signature
         headers.insert(SIGNATURE_HEADER, HeaderValue::from_str("invalid-signature").unwrap());
@@ -275,15 +355,49 @@ mod tests {
         assert_eq!(error.to_string(), "Invalid signature");
     }
 
+    #[test]
+    fn test_invalid_signature_log_contract_excludes_secrets() {
+        ensure_test_rpc_secret();
+        let url = "http://example.com/api/test";
+        let method = Method::GET;
+        let timestamp = OffsetDateTime::now_utc().unix_timestamp();
+        let secret = get_shared_secret().expect("test RPC secret should resolve");
+        let expected_signature = generate_signature(&secret, url, &method, timestamp);
+        let invalid_signature = "invalid-signature";
+        let logs = CapturedLogs::default();
+        let subscriber = tracing_subscriber::fmt()
+            .with_max_level(tracing::Level::ERROR)
+            .with_writer(logs.clone())
+            .with_ansi(false)
+            .without_time()
+            .finish();
+
+        let mut headers = HeaderMap::new();
+        headers.insert(SIGNATURE_HEADER, HeaderValue::from_str(invalid_signature).unwrap());
+        headers.insert(TIMESTAMP_HEADER, HeaderValue::from_str(&timestamp.to_string()).unwrap());
+
+        tracing::subscriber::with_default(subscriber, || {
+            let result = verify_rpc_signature(url, &method, &headers);
+            assert!(result.is_err(), "Invalid signature should fail verification");
+        });
+
+        let captured = logs.contents();
+        assert!(captured.contains("Invalid signature"));
+        assert!(!captured.contains(&secret));
+        assert!(!captured.contains(&expected_signature));
+        assert!(!captured.contains(invalid_signature));
+    }
+
     #[test]
     fn test_verify_rpc_signature_expired_timestamp() {
+        ensure_test_rpc_secret();
         let url = "http://example.com/api/test";
         let method = Method::GET;
         let mut headers = HeaderMap::new();
 
         // Set expired timestamp (older than SIGNATURE_VALID_DURATION)
         let expired_timestamp = OffsetDateTime::now_utc().unix_timestamp() - SIGNATURE_VALID_DURATION - 10;
-        let secret = get_shared_secret();
+        let secret = get_shared_secret().expect("test RPC secret should resolve");
         let signature = generate_signature(&secret, url, &method, expired_timestamp);
 
         headers.insert(SIGNATURE_HEADER, HeaderValue::from_str(&signature).unwrap());
@@ -297,6 +411,27 @@ mod tests {
         assert_eq!(error.to_string(), "Request timestamp expired");
     }
 
+    #[test]
+    fn test_verify_rpc_signature_future_timestamp_outside_window() {
+        ensure_test_rpc_secret();
+        let url = "http://example.com/api/test";
+        let method = Method::GET;
+        let mut headers = HeaderMap::new();
+
+        let future_timestamp = OffsetDateTime::now_utc().unix_timestamp() + SIGNATURE_VALID_DURATION + 10;
+        let secret = get_shared_secret().expect("test RPC secret should resolve");
+        let signature = generate_signature(&secret, url, &method, future_timestamp);
+
+        headers.insert(SIGNATURE_HEADER, HeaderValue::from_str(&signature).unwrap());
+        headers.insert(TIMESTAMP_HEADER, HeaderValue::from_str(&future_timestamp.to_string()).unwrap());
+
+        let result = verify_rpc_signature(url, &method, &headers);
+        assert!(result.is_err(), "Future timestamp outside valid window should fail verification");
+
+        let error = result.unwrap_err();
+        assert_eq!(error.to_string(), "Request timestamp expired");
+    }
+
     #[test]
     fn test_verify_rpc_signature_missing_signature_header() {
         let url = "http://example.com/api/test";
@@ -351,13 +486,14 @@ mod tests {
 
     #[test]
     fn test_verify_rpc_signature_url_mismatch() {
+        ensure_test_rpc_secret();
         let original_url = "http://example.com/api/test";
         let different_url = "http://example.com/api/different";
         let method = Method::GET;
         let mut headers = HeaderMap::new();
 
         // Build headers for one URL
-        build_auth_headers(original_url, &method, &mut headers);
+        build_auth_headers(original_url, &method, &mut headers).expect("auth headers should build");
 
         // Try to verify with a different URL
         let result = verify_rpc_signature(different_url, &method, &headers);
@@ -369,13 +505,14 @@ mod tests {
 
     #[test]
     fn test_verify_rpc_signature_method_mismatch() {
+        ensure_test_rpc_secret();
         let url = "http://example.com/api/test";
         let original_method = Method::GET;
         let different_method = Method::POST;
         let mut headers = HeaderMap::new();
 
         // Build headers for one method
-        build_auth_headers(url, &original_method, &mut headers);
+        build_auth_headers(url, &original_method, &mut headers).expect("auth headers should build");
 
         // Try to verify with a different method
         let result = verify_rpc_signature(url, &different_method, &headers);
@@ -387,9 +524,10 @@ mod tests {
 
     #[test]
     fn test_signature_valid_duration_boundary() {
+        ensure_test_rpc_secret();
         let url = "http://example.com/api/test";
         let method = Method::GET;
-        let secret = get_shared_secret();
+        let secret = get_shared_secret().expect("test RPC secret should resolve");
 
         let mut headers = HeaderMap::new();
         let current_time = OffsetDateTime::now_utc().unix_timestamp();
@@ -418,6 +556,7 @@ mod tests {
 
     #[test]
     fn test_round_trip_authentication() {
+        ensure_test_rpc_secret();
         let test_cases = vec![
             ("http://example.com/api/test", Method::GET),
             ("https://api.rustfs.com/v1/bucket", Method::POST),
@@ -429,7 +568,7 @@ mod tests {
             let mut headers = HeaderMap::new();
 
             // Build authentication headers
-            build_auth_headers(url, &method, &mut headers);
+            build_auth_headers(url, &method, &mut headers).expect("auth headers should build");
 
             // Verify the signature should succeed
             let result = verify_rpc_signature(url, &method, &headers);
diff --git a/crates/ecstore/src/rpc/remote_disk.rs b/crates/ecstore/src/rpc/remote_disk.rs
index eb58b0fd6..96aeaf577 100644
--- a/crates/ecstore/src/rpc/remote_disk.rs
+++ b/crates/ecstore/src/rpc/remote_disk.rs
@@ -1143,7 +1143,7 @@ impl DiskAPI for RemoteDisk {
 
                 let mut headers = HeaderMap::new();
                 headers.insert(CONTENT_TYPE, HeaderValue::from_static("application/json"));
-                build_auth_headers(&url, &Method::GET, &mut headers);
+                build_auth_headers(&url, &Method::GET, &mut headers)?;
 
                 let mut reader = HttpReader::new_with_stall_timeout(
                     url,
@@ -1196,7 +1196,7 @@ impl DiskAPI for RemoteDisk {
 
         let mut headers = HeaderMap::new();
         headers.insert(CONTENT_TYPE, HeaderValue::from_static("application/json"));
-        build_auth_headers(&url, &Method::GET, &mut headers);
+        build_auth_headers(&url, &Method::GET, &mut headers)?;
         Ok(Box::new(HttpReader::new(url, Method::GET, headers, None).await?))
     }
 
@@ -1239,7 +1239,7 @@ impl DiskAPI for RemoteDisk {
 
         let mut headers = HeaderMap::new();
         headers.insert(CONTENT_TYPE, HeaderValue::from_static("application/json"));
-        build_auth_headers(&url, &Method::PUT, &mut headers);
+        build_auth_headers(&url, &Method::PUT, &mut headers)?;
         Ok(Box::new(HttpWriter::new(url, Method::PUT, headers).await?))
     }
 
@@ -1270,7 +1270,7 @@ impl DiskAPI for RemoteDisk {
 
         let mut headers = HeaderMap::new();
         headers.insert(CONTENT_TYPE, HeaderValue::from_static("application/json"));
-        build_auth_headers(&url, &Method::PUT, &mut headers);
+        build_auth_headers(&url, &Method::PUT, &mut headers)?;
         Ok(Box::new(HttpWriter::new(url, Method::PUT, headers).await?))
     }
 
diff --git a/crates/ecstore/src/rpc/remote_locker.rs b/crates/ecstore/src/rpc/remote_locker.rs
index b39c1699a..82bd84a71 100644
--- a/crates/ecstore/src/rpc/remote_locker.rs
+++ b/crates/ecstore/src/rpc/remote_locker.rs
@@ -483,6 +483,10 @@ mod tests {
         GLOBAL_CONN_MAP.write().await.insert(addr.to_string(), channel);
     }
 
+    fn ensure_test_rpc_secret() {
+        let _ = rustfs_credentials::GLOBAL_RUSTFS_RPC_SECRET.set("test-rpc-secret".to_string());
+    }
+
     fn test_lock_request(timeout_duration: Duration) -> LockRequest {
         LockRequest::new(ObjectKey::new("bucket", "object"), LockType::Exclusive, "owner-a")
             .with_acquire_timeout(timeout_duration)
@@ -491,6 +495,7 @@ mod tests {
 
     #[tokio::test]
     async fn test_remote_client_acquire_lock_respects_request_timeout_and_evicts_connection() {
+        ensure_test_rpc_secret();
         let (addr, accept_task) = spawn_hanging_listener().await;
         cache_lazy_channel(&addr).await;
         assert!(GLOBAL_CONN_MAP.read().await.contains_key(&addr));
@@ -517,6 +522,7 @@ mod tests {
 
     #[tokio::test]
     async fn test_remote_client_acquire_locks_batch_respects_request_timeout_and_evicts_connection() {
+        ensure_test_rpc_secret();
         let (addr, accept_task) = spawn_hanging_listener().await;
         cache_lazy_channel(&addr).await;
         assert!(GLOBAL_CONN_MAP.read().await.contains_key(&addr));
diff --git a/rustfs/src/admin/handlers/profile.rs b/rustfs/src/admin/handlers/profile.rs
index b8ee18b77..6f6ebb29a 100644
--- a/rustfs/src/admin/handlers/profile.rs
+++ b/rustfs/src/admin/handlers/profile.rs
@@ -12,17 +12,41 @@
 //  See the License for the specific language governing permissions and
 //  limitations under the License.
 
-use crate::admin::router::Operation;
+use crate::admin::{auth::validate_admin_request, router::Operation};
+use crate::auth::{check_key_valid, get_session_token};
+use crate::server::RemoteAddr;
 use http::header::CONTENT_TYPE;
 use http::{HeaderMap, StatusCode};
 use matchit::Params;
-use s3s::{Body, S3Request, S3Response, S3Result};
+use rustfs_policy::policy::action::{Action, AdminAction};
+use s3s::{Body, S3Request, S3Response, S3Result, s3_error};
 use tracing::info;
 
+pub(super) async fn authorize_profile_request(req: &S3Request<Body>) -> S3Result<()> {
+    let Some(input_cred) = req.credentials.as_ref() else {
+        return Err(s3_error!(AccessDenied, "Signature is required"));
+    };
+
+    let (cred, owner) =
+        check_key_valid(get_session_token(&req.uri, &req.headers).unwrap_or_default(), &input_cred.access_key).await?;
+    let remote_addr = req.extensions.get::<Option<RemoteAddr>>().and_then(|opt| opt.map(|a| a.0));
+
+    validate_admin_request(
+        &req.headers,
+        &cred,
+        owner,
+        false,
+        vec![Action::AdminAction(AdminAction::ProfilingAdminAction)],
+        remote_addr,
+    )
+    .await
+}
+
 pub struct TriggerProfileCPU {}
 #[async_trait::async_trait]
 impl Operation for TriggerProfileCPU {
-    async fn call(&self, _req: S3Request<Body>, _params: Params<'_, '_>) -> S3Result<S3Response<(StatusCode, Body)>> {
+    async fn call(&self, req: S3Request<Body>, _params: Params<'_, '_>) -> S3Result<S3Response<(StatusCode, Body)>> {
+        authorize_profile_request(&req).await?;
         info!("Triggering CPU profile dump via S3 request...");
 
         let dur = std::time::Duration::from_secs(60);
@@ -40,7 +64,8 @@ impl Operation for TriggerProfileCPU {
 pub struct TriggerProfileMemory {}
 #[async_trait::async_trait]
 impl Operation for TriggerProfileMemory {
-    async fn call(&self, _req: S3Request<Body>, _params: Params<'_, '_>) -> S3Result<S3Response<(StatusCode, Body)>> {
+    async fn call(&self, req: S3Request<Body>, _params: Params<'_, '_>) -> S3Result<S3Response<(StatusCode, Body)>> {
+        authorize_profile_request(&req).await?;
         info!("Triggering Memory profile dump via S3 request...");
 
         match crate::profiling::dump_memory_pprof_now().await {
diff --git a/rustfs/src/admin/handlers/profile_admin.rs b/rustfs/src/admin/handlers/profile_admin.rs
index 9198070d9..4e2d830d6 100644
--- a/rustfs/src/admin/handlers/profile_admin.rs
+++ b/rustfs/src/admin/handlers/profile_admin.rs
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use super::profile::authorize_profile_request;
 use crate::admin::router::{AdminOperation, Operation, S3Router};
 use crate::server::ADMIN_PREFIX;
 use http::{HeaderMap, HeaderValue, Uri};
@@ -56,6 +57,8 @@ pub struct ProfileHandler {}
 #[async_trait::async_trait]
 impl Operation for ProfileHandler {
     async fn call(&self, req: S3Request<Body>, _params: Params<'_, '_>) -> S3Result<S3Response<(StatusCode, Body)>> {
+        authorize_profile_request(&req).await?;
+
         #[cfg(not(all(target_os = "linux", target_env = "gnu", target_arch = "x86_64")))]
         {
             let requested_url = req.uri.to_string();
@@ -151,7 +154,9 @@ pub struct ProfileStatusHandler {}
 
 #[async_trait::async_trait]
 impl Operation for ProfileStatusHandler {
-    async fn call(&self, _req: S3Request<Body>, _params: Params<'_, '_>) -> S3Result<S3Response<(StatusCode, Body)>> {
+    async fn call(&self, req: S3Request<Body>, _params: Params<'_, '_>) -> S3Result<S3Response<(StatusCode, Body)>> {
+        authorize_profile_request(&req).await?;
+
         #[cfg(not(all(target_os = "linux", target_env = "gnu", target_arch = "x86_64")))]
         let message = format!("CPU profiling is not supported on {} platform", std::env::consts::OS);
         #[cfg(not(all(target_os = "linux", target_env = "gnu", target_arch = "x86_64")))]
@@ -204,8 +209,26 @@ impl Operation for ProfileStatusHandler {
 
 #[cfg(test)]
 mod tests {
-    use super::extract_query_params;
-    use http::Uri;
+    use super::{ProfileHandler, ProfileStatusHandler, extract_query_params};
+    use crate::admin::router::Operation;
+    use http::{Extensions, HeaderMap, Uri};
+    use hyper::Method;
+    use matchit::Params;
+    use s3s::{Body, S3ErrorCode, S3Request};
+
+    fn build_profile_request(uri: &'static str) -> S3Request<Body> {
+        S3Request {
+            input: Body::empty(),
+            method: Method::GET,
+            uri: Uri::from_static(uri),
+            headers: HeaderMap::new(),
+            extensions: Extensions::new(),
+            credentials: None,
+            region: None,
+            service: None,
+            trailing_headers: None,
+        }
+    }
 
     #[test]
     fn test_extract_query_params_decodes_percent_encoded_values() {
@@ -217,4 +240,32 @@ mod tests {
         assert_eq!(params.get("format"), Some(&"flamegraph".to_string()));
         assert_eq!(params.get("note"), Some(&"a+b value".to_string()));
     }
+
+    #[tokio::test]
+    async fn profile_handler_rejects_missing_credentials() {
+        let result = ProfileHandler {}
+            .call(build_profile_request("/rustfs/admin/debug/pprof/profile?format=protobuf"), Params::new())
+            .await;
+        let err = match result {
+            Ok(_) => panic!("profile handler must reject unauthenticated requests"),
+            Err(err) => err,
+        };
+
+        assert_eq!(err.code(), &S3ErrorCode::AccessDenied);
+        assert_eq!(err.message(), Some("Signature is required"));
+    }
+
+    #[tokio::test]
+    async fn profile_status_handler_rejects_missing_credentials() {
+        let result = ProfileStatusHandler {}
+            .call(build_profile_request("/rustfs/admin/debug/pprof/status"), Params::new())
+            .await;
+        let err = match result {
+            Ok(_) => panic!("profile status handler must reject unauthenticated requests"),
+            Err(err) => err,
+        };
+
+        assert_eq!(err.code(), &S3ErrorCode::AccessDenied);
+        assert_eq!(err.message(), Some("Signature is required"));
+    }
 }
diff --git a/rustfs/src/admin/handlers/sts.rs b/rustfs/src/admin/handlers/sts.rs
index bc72f2a92..b669f8ff4 100644
--- a/rustfs/src/admin/handlers/sts.rs
+++ b/rustfs/src/admin/handlers/sts.rs
@@ -250,7 +250,12 @@ async fn handle_assume_role(
 
     new_cred.parent_user = cred.access_key.clone();
 
-    debug!("AssumeRole get new_cred {:?}", &new_cred);
+    debug!(
+        access_key = %new_cred.access_key,
+        parent_user = %new_cred.parent_user,
+        expiration = ?new_cred.expiration,
+        "AssumeRole generated temporary credentials"
+    );
 
     let updated_at = iam_store
         .set_temp_user(&new_cred.access_key, &new_cred, None)
diff --git a/rustfs/src/admin/handlers/user.rs b/rustfs/src/admin/handlers/user.rs
index 18e553744..cd46a1112 100644
--- a/rustfs/src/admin/handlers/user.rs
+++ b/rustfs/src/admin/handlers/user.rs
@@ -139,6 +139,36 @@ fn imported_service_account_status(status: &str) -> Option<String> {
     None
 }
 
+const SERVICE_ACCOUNT_PARENT_SCOPE_ERROR: &str = "service account parent is outside requester scope";
+
+fn imported_service_account_parent_allowed(parent: &str, requester: &Credentials, owner: bool) -> bool {
+    if parent.is_empty() {
+        return false;
+    }
+
+    if owner {
+        return true;
+    }
+
+    if requester.is_temp() || requester.is_service_account() {
+        return temp_identity_parent(requester).is_some_and(|requester_parent| requester_parent == parent);
+    }
+
+    requester.parent_user.is_empty() && requester.access_key == parent
+}
+
+fn imported_service_account_parent_scope_failure(
+    access_key: &str,
+    parent: &str,
+    requester: &Credentials,
+    owner: bool,
+) -> Option<IAMErrEntity> {
+    (!imported_service_account_parent_allowed(parent, requester, owner)).then(|| IAMErrEntity {
+        name: access_key.to_string(),
+        error: SERVICE_ACCOUNT_PARENT_SCOPE_ERROR.to_string(),
+    })
+}
+
 pub struct AddUser {}
 #[async_trait::async_trait]
 impl Operation for AddUser {
@@ -984,6 +1014,11 @@ impl Operation for ImportIam {
                         return Err(s3_error!(InvalidArgument, "has space be {ak}"));
                     }
 
+                    if let Some(err) = imported_service_account_parent_scope_failure(&ak, &req.parent, &cred, owner) {
+                        failed.service_accounts.push(err);
+                        continue;
+                    }
+
                     let mut update = true;
 
                     if let Err(e) = iam_store.get_service_account(&req.access_key).await {
@@ -1216,8 +1251,9 @@ impl Operation for ImportIam {
 #[cfg(test)]
 mod tests {
     use super::{
-        GROUP_POLICY_MAPPING_USER_TYPE, imported_service_account_status, should_check_deny_only, should_reject_group_import_name,
-        should_restore_group_as_disabled,
+        GROUP_POLICY_MAPPING_USER_TYPE, SERVICE_ACCOUNT_PARENT_SCOPE_ERROR, imported_service_account_parent_allowed,
+        imported_service_account_parent_scope_failure, imported_service_account_status, should_check_deny_only,
+        should_reject_group_import_name, should_restore_group_as_disabled,
     };
     use rustfs_credentials::{Credentials, IAM_POLICY_CLAIM_NAME_SA};
     use rustfs_iam::error::Error as IamError;
@@ -1337,6 +1373,65 @@ mod tests {
         assert!(imported_service_account_status("unknown").is_none());
     }
 
+    #[test]
+    fn test_import_service_account_parent_rejects_other_parent_for_non_owner() {
+        let requester = Credentials {
+            access_key: "delegated-importer".to_string(),
+            ..Default::default()
+        };
+
+        assert!(!imported_service_account_parent_allowed("root-access-key", &requester, false));
+    }
+
+    #[test]
+    fn test_service_account_parent_scope_failure_records_import_error() {
+        let requester = Credentials {
+            access_key: "delegated-importer".to_string(),
+            ..Default::default()
+        };
+        let err = imported_service_account_parent_scope_failure("svc-access-key", "root-access-key", &requester, false)
+            .expect("non-owner must not import a service account for another parent");
+
+        assert_eq!(err.name, "svc-access-key");
+        assert_eq!(err.error, SERVICE_ACCOUNT_PARENT_SCOPE_ERROR);
+        assert!(
+            imported_service_account_parent_scope_failure("svc-access-key", "delegated-importer", &requester, false).is_none()
+        );
+    }
+
+    #[test]
+    fn test_import_service_account_parent_allows_owner_restore() {
+        let requester = Credentials {
+            access_key: "root-access-key".to_string(),
+            ..Default::default()
+        };
+
+        assert!(imported_service_account_parent_allowed("any-imported-parent", &requester, true));
+    }
+
+    #[test]
+    fn test_import_service_account_parent_allows_requester_self_parent() {
+        let requester = Credentials {
+            access_key: "delegated-importer".to_string(),
+            ..Default::default()
+        };
+
+        assert!(imported_service_account_parent_allowed("delegated-importer", &requester, false));
+    }
+
+    #[test]
+    fn test_import_service_account_parent_allows_derived_requester_parent() {
+        let requester = Credentials {
+            access_key: "derived-access-key".to_string(),
+            parent_user: "parent-user".to_string(),
+            session_token: "session-token".to_string(),
+            ..Default::default()
+        };
+
+        assert!(imported_service_account_parent_allowed("parent-user", &requester, false));
+        assert!(!imported_service_account_parent_allowed("other-parent", &requester, false));
+    }
+
     #[test]
     fn test_service_account_import_accepts_null_groups_and_epoch_expiration() {
         let payload = r#"{
diff --git a/rustfs/src/admin/router.rs b/rustfs/src/admin/router.rs
index f9d4eb079..37edd3804 100644
--- a/rustfs/src/admin/router.rs
+++ b/rustfs/src/admin/router.rs
@@ -2331,11 +2331,6 @@ where
         // Allow unauthenticated access to health check
         let path = req.uri.path();
 
-        // Profiling endpoints
-        if req.method == Method::GET && (path == PROFILE_CPU_PATH || path == PROFILE_MEMORY_PATH) {
-            return Ok(());
-        }
-
         // Health check
         if (req.method == Method::HEAD || req.method == Method::GET) && is_public_health_path(path) {
             return Ok(());
@@ -3747,6 +3742,28 @@ mod tests {
         assert_eq!(err.code(), &S3ErrorCode::AccessDenied);
     }
 
+    #[tokio::test]
+    async fn check_access_rejects_anonymous_profile_request() {
+        let router: S3Router<AdminOperation> = S3Router::new(false);
+        let mut req = S3Request {
+            input: Body::from(String::new()),
+            method: Method::GET,
+            uri: PROFILE_CPU_PATH.parse().expect("uri should parse"),
+            headers: HeaderMap::new(),
+            extensions: http::Extensions::new(),
+            credentials: None,
+            region: None,
+            service: None,
+            trailing_headers: None,
+        };
+
+        let err = router
+            .check_access(&mut req)
+            .await
+            .expect_err("anonymous profile request must be denied");
+        assert_eq!(err.code(), &S3ErrorCode::AccessDenied);
+    }
+
     #[test]
     fn listen_notification_keepalive_plan_defaults_to_space_keepalive() {
         let uri: Uri = "/demo-bucket?events=s3:ObjectCreated:Put".parse().expect("uri should parse");