---
id: CVE-2026-29000
title: >-
  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
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 …
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-347
vendor: pac4j
product: pac4j-jwt
affected:
  - pac4j-jwt >= 4.0 < 4.5.9
  - pac4j-jwt >= 5.0 < 5.7.9
  - pac4j-jwt >= 6.0 < 6.3.3
published: '2026-03-04'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T16:17:12.670'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-29000'
references:
  - url: >-
      https://www.codeant.ai/security-research/pac4j-jwt-authentication-bypass-public-key
    label: disclosure@vulncheck.com
  - url: >-
      https://www.pac4j.org/blog/security-advisory-pac4j-jwt-jwtauthenticator.html
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/pac4j-jwt-jwtauthenticator-authentication-bypass
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-03-07T04:55:36.270180Z'
epss: 0.00502
epssPercentile: 0.41007
exploits:
  github: 21
  githubRepos:
    - 'https://github.com/kernelzeroday/CVE-2026-29000'
    - 'https://github.com/Strikoder-Premium/CVE-2026-29000-pac4j-jwt'
    - 'https://github.com/tc4dy/CVE-2026-29000-PoC-Exploit'
  checkedAt: '2026-10-08T16:52:49.760Z'
ingestedAt: '2026-10-08T16:52:14.674Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.