CVE-2026-29000: CWE-347 Improper Verification of Cryptographic Signature in pac4j pac4j-jwt
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.
AI Analysis
Technical Summary
CVE-2026-29000 is an authentication bypass vulnerability in pac4j-jwt's JwtAuthenticator component affecting versions before 4.5.9, 5.7.9, and 6.3.3. The issue arises from improper verification of cryptographic signatures (CWE-347) when processing encrypted JWTs. Attackers possessing the server's RSA public key can craft a JWE-wrapped PlainJWT containing arbitrary subject and role claims, bypassing signature verification and gaining unauthorized access as any user, including privileged accounts.
Potential Impact
Successful exploitation allows remote attackers to bypass authentication controls and impersonate any user, including administrators, potentially leading to full system compromise or unauthorized access to sensitive resources. The vulnerability has a CVSS 4.0 base score of 9.3, indicating critical severity with network attack vector, no required privileges or user interaction, and high impact on confidentiality and integrity.
Mitigation Recommendations
The vulnerability affects pac4j-jwt versions prior to 4.5.9, 5.7.9, and 6.3.3. Users should upgrade to at least these fixed versions to remediate the issue. No patch links were provided in the input, but the version numbers indicate that official fixes exist. Until upgrading, restrict access to the server's RSA public key and monitor for suspicious token usage. Patch status is confirmed by version numbers indicating fixed releases; therefore, remediation is available.
CVE-2026-29000: CWE-347 Improper Verification of Cryptographic Signature in pac4j pac4j-jwt
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.
CVSS v4.0
Score 9.3critical
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-29000 is an authentication bypass vulnerability in pac4j-jwt's JwtAuthenticator component affecting versions before 4.5.9, 5.7.9, and 6.3.3. The issue arises from improper verification of cryptographic signatures (CWE-347) when processing encrypted JWTs. Attackers possessing the server's RSA public key can craft a JWE-wrapped PlainJWT containing arbitrary subject and role claims, bypassing signature verification and gaining unauthorized access as any user, including privileged accounts.
Potential Impact
Successful exploitation allows remote attackers to bypass authentication controls and impersonate any user, including administrators, potentially leading to full system compromise or unauthorized access to sensitive resources. The vulnerability has a CVSS 4.0 base score of 9.3, indicating critical severity with network attack vector, no required privileges or user interaction, and high impact on confidentiality and integrity.
Mitigation Recommendations
The vulnerability affects pac4j-jwt versions prior to 4.5.9, 5.7.9, and 6.3.3. Users should upgrade to at least these fixed versions to remediate the issue. No patch links were provided in the input, but the version numbers indicate that official fixes exist. Until upgrading, restrict access to the server's RSA public key and monitor for suspicious token usage. Patch status is confirmed by version numbers indicating fixed releases; therefore, remediation is available.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-03-03T16:42:01.012Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 69a8ac26d1a09e29cb796104
Added to database: 3/4/2026, 10:03:18 PM
Last enriched: 5/12/2026, 4:04:28 AM
Last updated: 6/3/2026, 5:18:38 AM
Views: 2986
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