CVE-2026-29000: pac4j-jwt: JwtAuthenticator Authentication Bypass via JWE-Wrapped PlainJWT
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…
Published Mar 5, 2026 · Updated Mar 6, 2026
Affected packages
org.pac4j:pac4j-jwt
- Ecosystem
- Maven
- Affected
- >= 6.0.4.1, < 6.3.3
- Fixed in
- 6.3.3
- Check
mvn dependency:tree -Dincludes=org.pac4j:pac4j-jwt
org.pac4j:pac4j-jwt
- Ecosystem
- Maven
- Affected
- >= 5.0.0-RC1, < 5.7.9
- Fixed in
- 5.7.9
- Check
mvn dependency:tree -Dincludes=org.pac4j:pac4j-jwt
org.pac4j:pac4j-jwt
- Ecosystem
- Maven
- Affected
- < 4.5.9
- Fixed in
- 4.5.9
- Check
mvn dependency:tree -Dincludes=org.pac4j:pac4j-jwt
Advisory details
From the GitHub Advisory Database (CC BY 4.0).
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.
Credited to fritzdal.
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-29000
- https://www.codeant.ai/security-research/pac4j-jwt-authentication-bypass-public-key
- https://www.pac4j.org/blog/security-advisory-pac4j-jwt-jwtauthenticator.html
- https://www.vulncheck.com/advisories/pac4j-jwt-jwtauthenticator-authentication-bypass
- https://github.com/advisories/GHSA-pm7g-w2cf-q238
How this page is made: the data panel comes from the GitHub Advisory Database, CISA’s KEV catalog, the NVD and FIRST EPSS, and updates twice a day. No analysis has been written for this entry yet. Methodology