Laravel TokenGuard authentication bypass through non-string API credentials

An unauthenticated attacker may sign in as an existing user without knowing their valid API token, potentially taking over that account on routes protected by the affected guard. This affects Laravel's built-in TokenGuard when configured as a standard token-based API guard, under certain MySQL/MariaDB database configurations where a non-string credential is mishandled during authentication.

Look for laravel/framework in composer.lock. Affected versions are below 12.68.0, or at least 13.0.0 but below 13.29.0; the fixes are 12.68.0 and 13.29.0. Check whether your application uses the built-in TokenGuard as a standard token-based API guard with MySQL/MariaDB, and which routes it protects. The advisory does not specify which database configurations trigger the flaw.

Laravel's built-in TokenGuard, when configured with a standard token-based API guard, may be bypassed to authenticate as an arbitrary existing user without knowledge of their valid API token.

Under certain database configurations (MySQL/MariaDB) an attacker can submit a specially crafted, non-string credential value that is mishandled during the authentication lookup, causing the underlying query to match an unintended user record rather than failing authentication as expected.

Impact

An unauthenticated attacker may authenticate as another user without possessing that user's API token, leading to authentication bypass and account takeover on any route protected by the affected guard.