CVE-2026-29000 json
pac4j-jwt JwtAuthenticator Authentication Bypass
published 2026-03-04 8 mo ago modified 2026-10-08 31 d ago also EUVD-2026-9505 , GHSA-pm7g-w2cf-q238
- cvss
- 9.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 6.2%
- EPSS 6.2% chance of exploitation in 30 days, percentile 93%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- maven org.pac4j:pac4j-jwt 4.5.9, 5.7.9, 6.3.3
- pac4j pac4j-jwt 4.5.9, 5.7.9, 6.3.3
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- total
- Assessed
- 8 mo ago
Exploit prediction
6.17% chance of exploitation in the next 30 days, higher than 93% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- codeant.ai https://www.codeant.ai/security-research/pac4j-jwt-authentication-bypass-public-key referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 9.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N |
| CNA | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| GitHub | 3.1 | 10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L |
| CNA | 4.0 | 9.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| maven | org.pac4j:pac4j-jwt | >=6.0.4.1, <6.3.3 >=5.0.0-RC1, <5.7.9 <4.5.9 |
6.3.3 5.7.9 4.5.9 |
Affected products
- pac4j pac4j-jwt
Classification
- Weakness
-
- CWE-347 Improper Verification of Cryptographic Signature
References
-
codeant.ai
/security-research/pac4j-jwt-authentication-bypass-public-key
technical-description, exploit, web
-
pac4j.org
/blog/security-advisory-pac4j-jwt-jwtauthenticator.html
vendor-advisory, web
-
vulncheck.com
/advisories/pac4j-jwt-jwtauthenticator-authentication-bypass
third-party-advisory, web
-
nvd.nist.gov
/vuln/detail/CVE-2026-29000
advisory
-
github.com
/pac4j/pac4j
package
Sources
- CVE List CVE-2026-29000
- GitHub Advisory GHSA-pm7g-w2cf-q238
- NVD CVE-2026-29000
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.