CVE-2026-29000

CRITICAL 9.1

pac4j-jwt JwtAuthenticator Authentication Bypass

CVSS Score

9.1

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-347
Vendor	pac4j
Product	pac4j-jwt
Published	Mar 4, 2026
Last Updated	Mar 11, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Affected Versions

pac4j / pac4j-jwt

4.0 < 4.5.9 5.0 < 5.7.9 6.0 < 6.3.3

References

NVD ↗ CVE.org ↗ EPSS Data ↗

pac4j.org: https://www.pac4j.org/blog/security-advisory-pac4j-jwt-jwtauthenticator.html codeant.ai: https://www.codeant.ai/security-research/pac4j-jwt-authentication-bypass-public-key vulncheck.com: https://www.vulncheck.com/advisories/pac4j-jwt-jwtauthenticator-authentication-bypass

Credits

CodeAnt AI Security