pac4j-jwt: JwtAuthenticator Authentication Bypass via JWE-Wrapped PlainJWTGHSA-pm7g-w2cf-q238
CRITICALGHSA-pm7g-w2cf-q238 is a critical-severity (CVSS 10) CWE-347 vulnerability in org.pac4j:pac4j-jwt. 3 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for org.pac4j:pac4j-jwt — see the affected versions and patch details below.
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for GHSA-pm7g-w2cf-q238.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
org.pac4j:pac4j-jwt☕org.pac4j:pac4j-jwt☕org.pac4j:pac4j-jwtReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.pac4j:pac4j-jwt | ≥ 6.0.4.1&&< 6.3.3 | 6.3.3org.pac4j:pac4j-jwt:6.3.3 |
| ☕Maven | org.pac4j:pac4j-jwt | ≥ 5.0.0-RC1&&< 5.7.9 | 5.7.9org.pac4j:pac4j-jwt:5.7.9 |
| ☕Maven | org.pac4j:pac4j-jwt | all versions | 4.5.9org.pac4j:pac4j-jwt:4.5.9 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
kernelzeroday/CVE-2026-29000
pac4j-jwt JwtAuthenticator auth bypass (CVE-2026-29000) writeup and PoCs
Strikoder-Premium/CVE-2026-29000-pac4j-jwt
CVE-2026-29000 PoC: pac4j-jwt PlainJWT-in-JWE authentication bypass.
tc4dy/CVE-2026-29000-PoC-Exploit
CVE-2026-29000 – pac4j-jwt Authentication Bypass (🔥 CVSS 10.0). One-cli
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.pac4j:pac4j-jwt, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.pac4j:pac4j-jwt to 6.3.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pm7g-w2cf-q238 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is GHSA-pm7g-w2cf-q238 in your dependencies?
Find it across Maven, including transitive dependencies.