CVE-2026-29000

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 products

Pac4J-Jwt

Fix

Available

CVSS 4.0

9.3 CRITICAL

CVSS 3.1

9.1 CRITICAL

EPSS

5.9% (93th percentile)

Weakness

CWE-347

NVD status

Deferred

Published

2026-03-04