Yoo guys. CVE-2026-29000. Anyone with your server's public key can forge admin tokens. If you're running any Java-based selfhosted app that uses pac4j for authentication, you're exposed.

Writeup: https://www.codeant.ai/security-research/pac4j-jwt-authentication-bypass-public-key

Affected: pac4j-jwt < 4.5.9 / < 5.7.9 / < 6.3.3

Check your JARs. ⁠ grep -r "pac4j" your-app/lib/ ⁠ or check your dependency tree.

pac4j-jwt versions prior to 4.5.9, 5.7.9, and 6.3.3 contain an authentication bypass vulnerability in JwtAuthenticator when processing encrypted JWTs that allows remote attackers to forge authentication tokens. Attackers who possess the server's RSA public key can create a JWE-wrapped PlainJWT with arbitrary subject and role claims, bypassing signature verification to authenticate as any user including administrators.

Credits: CodeAnt AI Security