CVE-2026-29000 — pac4j-jwt
CVE-2026-29000 is a CWE-347 vulnerability in org.pac4j:pac4j-jwt. 3 public exploit references exist, so weaponization risk is real. A fix is available for org.pac4j:pac4j-jwt — see the affected versions and patch details below.
pac4j-jwt JwtAuthenticator Authentication Bypass
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 CVE-2026-29000.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
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 CVE-2026-29000 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-29000 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-29000. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-29000 in your dependencies?
O3 Security finds CVE-2026-29000 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.