A high-severity authentication bypass vulnerability in pac4j-core allows authenticated attackers to escalate privileges and access unauthorized resources.

The vulnerability resides in the CheckProfileTypeAuthorizer class, where a logic flaw reverses the validation of profile types. An attacker with low-level authentication can successfully satisfy generic profile checks to gain access to resources intended only for higher-privileged user profiles.

This vulnerability poses a significant risk to data confidentiality and system integrity. Because the flaw allows an attacker to bypass authorization controls, unauthorized parties may gain access to sensitive administrative functions or protected data, leading to potential data breaches or unauthorized administrative actions. With a CVSS score of 8.1, the high severity reflects the ease of exploitation and the significant impact on application security.

Immediate Action: Upgrade the pac4j-core library to version 6.5.6 or higher to resolve the authorization logic error.

Proactive Monitoring: Review application access logs for unusual patterns, such as standard users accessing administrative endpoints or resources typically restricted to specific user roles.

Compensating Controls: If immediate patching is not feasible, implement strict server-side authorization checks at the application level that do not rely solely on the vulnerable CheckProfileTypeAuthorizer component.

Public Exploit Available: No

The authorization bypass in pac4j-core represents a critical failure in access control logic that should be addressed immediately. Development teams using this library must prioritize updating to version 6.5.6 to ensure that authorization checks function as intended and to prevent potential privilege escalation within their applications.