In Spring Security, an application is vulnerable to broken access control when it directly uses the AuthenticationTrustResolver.isFullyAuthenticated(Authentication) method.

Specifically, an application is vulnerable if:

• The application uses AuthenticationTrustResolver.isFullyAuthenticated(Authentication) directly and a null authentication parameter is passed to it resulting in an erroneous true return value.

An application is not vulnerable if any of the following is true:

• The application does not use AuthenticationTrustResolver.isFullyAuthenticated(Authentication) directly.
• The application does not pass null to AuthenticationTrustResolver.isFullyAuthenticated
• The application only uses isFullyAuthenticated via Method Security or HTTP Request Security