@acastellon/auth v2.2.0 appears to allow an unauthenticated authentication bypass in validateToken() through spoofable auth-user and Host request headers. The validateToken middleware contains a service-to-service bypass for auth-user: service-brother when req.get('host').startsWith(getHostName()). Both values involved in the check can be influenced by an unauthenticated HTTP client: auth-user is a request header, and Host is also client-controlled. As a result, a remote unauthenticated attacker can send a request with crafted headers and bypass token validation before the normal legacy/JWT/OIDC validation logic runs. Impact: An attacker may be able to access routes protected by validateToken() without a valid token. In deployments where downstream services trust auth-user or is-* headers, this may also lead to privilege escalation. Affected package: @acastellon/auth v2.2.0 Affected code: auth.js, validateToken() The issue is related to the service-brother bypass and getHostName() check. Example request: ``` GET /protected HTTP/1.1 Host: <configured CNAME or hostname> auth-user: service-brother is-admin: true ``` Expected behavior: The request should require a valid authentication token. Actual behavior: The middleware calls next() before token validation. Fix implemented in v2.3.0+: Removed the spoofable bypass. Always sanitize incoming auth-user and is-* headers. Added mTLS client certificate based service auth (with optional TRUSTED_MTLS_SERVICES allowlist). Updated consumers (rest, graphql, dns-client) for mTLS support. Unit tests added for sanitization + mTLS path.
@acastellon/auth v2.2.0 appears to allow an unauthenticated authentication bypass in validateToken() through spoofable auth-user and Host request headers. The validateToken middleware contains a service-to-service bypass for auth-user: service-brother when req.get('host').startsWith(getHostName()). Both values involved in the check can be influenced by an unauthenticated HTTP client: auth-user is a request header, and Host is also client-controlled. As a result, a remote unauthenticated attacker can send a request with crafted headers and bypass token validation before the normal legacy/JWT/OIDC validation logic runs. Impact: An attacker may be able to access routes protected by validateToken() without a valid token. In deployments where downstream services trust auth-user or is-* headers, this may also lead to privilege escalation. Affected package: @acastellon/auth v2.2.0 Affected code: auth.js, validateToken() The issue is related to the service-brother bypass and getHostName() check. Example request: ``` GET /protected HTTP/1.1 Host: <configured CNAME or hostname> auth-user: service-brother is-admin: true ``` Expected behavior: The request should require a valid authentication token. Actual behavior: The middleware calls next() before token validation. Fix implemented in v2.3.0+: Removed the spoofable bypass. Always sanitize incoming auth-user and is-* headers. Added mTLS client certificate based service auth (with optional TRUSTED_MTLS_SERVICES allowlist). Updated consumers (rest, graphql, dns-client) for mTLS support. Unit tests added for sanitization + mTLS path.
Update @acastellon/auth to 2.3.0 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scan@acastellon/auth: Authentication bypass via spoofable headers in validateToken() affects @acastellon/auth (npm). Severity is critical. @acastellon/auth v2.2.0 appears to allow an unauthenticated authentication bypass in validateToken() through spoofable auth-user and Host request headers. The validateToken middleware contains a service-to-service bypass for auth-user: service-brother when req.get('host').startsWith(getHostName()). Both values involved in the check can be influenced by an unauthenticated HTTP client: auth-user is a request header, and Host is also client-controlled. As a result, a remote unauthenticated attacker can send a request with crafted headers and bypass token validation before the normal legacy/JWT/OIDC validation logic runs. Impact: An attacker may be able to access routes protected by validateToken() without a valid token. In deployments where downstream services trust auth-user or is-* headers, this may also lead to privilege escalation. Affected package: @acastellon/auth v2.2.0 Affected code: auth.js, validateToken() The issue is related to the service-brother bypass and getHostName() check. Example request: ``` GET /protected HTTP/1.1 Host: <configured CNAME or hostname> auth-user: service-brother is-admin: true ``` Expected behavior: The request should require a valid authentication token. Actual behavior: The middleware calls next() before token validation. Fix implemented in v2.3.0+: Removed the spoofable bypass. Always sanitize incoming auth-user and is-* headers. Added mTLS client certificate based service auth (with optional TRUSTED_MTLS_SERVICES allowlist). Updated consumers (rest, graphql, dns-client) for mTLS support. Unit tests added for sanitization + mTLS path.
AI coding agents often install or upgrade packages automatically in npm. A critical vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| @acastellon/authnpm | <2.3.0 | 2.3.0 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardUpdate @acastellon/auth to 2.3.0 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scan@acastellon/auth: Authentication bypass via spoofable headers in validateToken() affects @acastellon/auth (npm). Severity is critical. @acastellon/auth v2.2.0 appears to allow an unauthenticated authentication bypass in validateToken() through spoofable auth-user and Host request headers. The validateToken middleware contains a service-to-service bypass for auth-user: service-brother when req.get('host').startsWith(getHostName()). Both values involved in the check can be influenced by an unauthenticated HTTP client: auth-user is a request header, and Host is also client-controlled. As a result, a remote unauthenticated attacker can send a request with crafted headers and bypass token validation before the normal legacy/JWT/OIDC validation logic runs. Impact: An attacker may be able to access routes protected by validateToken() without a valid token. In deployments where downstream services trust auth-user or is-* headers, this may also lead to privilege escalation. Affected package: @acastellon/auth v2.2.0 Affected code: auth.js, validateToken() The issue is related to the service-brother bypass and getHostName() check. Example request: ``` GET /protected HTTP/1.1 Host: <configured CNAME or hostname> auth-user: service-brother is-admin: true ``` Expected behavior: The request should require a valid authentication token. Actual behavior: The middleware calls next() before token validation. Fix implemented in v2.3.0+: Removed the spoofable bypass. Always sanitize incoming auth-user and is-* headers. Added mTLS client certificate based service auth (with optional TRUSTED_MTLS_SERVICES allowlist). Updated consumers (rest, graphql, dns-client) for mTLS support. Unit tests added for sanitization + mTLS path.
AI coding agents often install or upgrade packages automatically in npm. A critical vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| @acastellon/authnpm | <2.3.0 | 2.3.0 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard