SB2026030924 - Authentication bypass in pac4j
Published: March 9, 2026
Security Bulletin ID
SB2026030924
Severity
Critical
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Code execution
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Improper verification of cryptographic signature (CVE-ID: CVE-2026-29000)
The vulnerability allows a remote attacker to bypass authentication checks.
The vulnerability exists due to an error in JwtAuthenticator when processing encrypted JWTs. A remote non-authenticated attacker with possession of the server's RSA public key can create a JWE-wrapped PlainJWT with arbitrary subject and role claims, bypass signature verification and authenticated as any user including administrators.
Remediation
Install update from vendor's website.