Improper Verification of Cryptographic Signature Affecting org.pac4j:pac4j-jwt package, versions [,4.5.9)[5.0.0-RC1,5.7.9)[6.0.0-RC1,6.3.3)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JAVA-ORGPAC4J-15428218
- published6 Mar 2026
- disclosed5 Mar 2026
- creditCodeAnt AI Security Research Team
Introduced: 5 Mar 2026
CVE-2026-29000 (opens in a new tab)How to fix?
Upgrade org.pac4j:pac4j-jwt to version 4.5.9, 5.7.9, 6.3.3 or higher.
Overview
Affected versions of this package are vulnerable to Improper Verification of Cryptographic Signature in the JwtAuthenticator component when handling encrypted JWTs. An attacker can gain unauthorized access by crafting a JWE-wrapped PlainJWT with arbitrary claims if they possess the server's RSA public key, thereby impersonating any user, including administrators.