10.0
CRITICAL CVSS 4.0
CVE-2026-29000
pac4j-jwt JwtAuthenticator Authentication Bypass
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.

INFO

Published Date :

March 4, 2026, 10:16 p.m.

Last Modified :

April 16, 2026, 4:18 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-29000 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Pac4j pac4j
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 CRITICAL 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 3.1 CRITICAL [email protected]
CVSS 3.1 CRITICAL MITRE-CVE
CVSS 3.1 CRITICAL [email protected]
CVSS 4.0 CRITICAL 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 4.0 CRITICAL [email protected]
CVSS 4.0 CRITICAL [email protected]
Solution
Update pac4j-jwt to a patched version to prevent JWT authentication bypass via forged tokens.
  • Update pac4j-jwt to version 4.5.9 or later.
  • Update pac4j-jwt to version 5.7.9 or later.
  • Update pac4j-jwt to version 6.3.3 or later.
Public PoC/Exploit Available at Github

CVE-2026-29000 has a 33 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-29000.

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

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-29000 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-29000 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

🚀 CVE-2026-24061 - GNU inetutils-telnetd Auth Bypass Exploit - Full Control 💥 CRLF injection via NEW_ENVIRON leads to auth bypass & instant root shell. ✅ Single/Mass exploitation, multi-threading, custom port/user, pipe mode, session keep-alive, colored output, retries, timeout support. ⚡ Python & Bash versions. Critical CVSS 9.8.

Python Shell

Updated: 2 weeks ago
0 stars 0 fork 0 watcher
Born at : June 6, 2026, 12:38 p.m. This repo has been linked 4 different CVEs too.

None

Dockerfile Java PowerShell Shell Batchfile Python Bru

Updated: 2 weeks, 3 days ago
0 stars 0 fork 0 watcher
Born at : June 1, 2026, 10:42 a.m. This repo has been linked 1 different CVEs too.

Python POC, Exploit for CVE-2026-29000

Python

Updated: 3 weeks, 1 day ago
0 stars 0 fork 0 watcher
Born at : May 30, 2026, 7:34 a.m. This repo has been linked 1 different CVEs too.

None

Updated: 3 weeks, 5 days ago
0 stars 0 fork 0 watcher
Born at : May 25, 2026, 10:54 p.m. This repo has been linked 1 different CVEs too.

None

Dockerfile JavaScript Python HTML CSS Shell Java

Updated: 1 month ago
2 stars 0 fork 0 watcher
Born at : May 18, 2026, 7:30 p.m. This repo has been linked 5 different CVEs too.

🚀 CVE-2026-0073 - Android ADB Wireless Debugging Exploit (CVSS 8.8) 🔓 Zero-click authentication bypass via TLS type confusion. Gain interactive shell, execute commands, scan networks. Educational red-team tool. 🐚⚡

Python

Updated: 1 week, 6 days ago
1 stars 3 fork 3 watcher
Born at : May 13, 2026, 2:28 p.m. This repo has been linked 4 different CVEs too.

CVE-2026-29000 – pac4j-jwt Authentication Bypass (🔥 CVSS 10.0). One-click admin forge via public key JWE wrapping. Leaks configs, users, secrets. Keep-alive, proxy, custom JWKS.⚙️ Educational PoC Exploit tool.

Python

Updated: 2 weeks, 1 day ago
0 stars 0 fork 0 watcher
Born at : May 12, 2026, 4:03 p.m. This repo has been linked 1 different CVEs too.

🚀 CVE-2026-41940 cPanel/WHM Auth Bypass Exploit - Best Flow 💥 CRLF injection leads to auth bypass, session hijacking & account leak. ✅ Proxy, custom UA, keep-alive, retries, SSL verify, colored output, file save support. ⚡ Advanced PoC for pentesters.

Python

Updated: 2 weeks ago
1 stars 0 fork 0 watcher
Born at : May 12, 2026, 2:47 p.m. This repo has been linked 4 different CVEs too.

None

Updated: 1 month, 1 week ago
0 stars 0 fork 0 watcher
Born at : May 11, 2026, 9:38 a.m. This repo has been linked 1 different CVEs too.

Personal writeup of the Principal hack the box machine

Python

Updated: 1 month, 1 week ago
1 stars 0 fork 0 watcher
Born at : May 6, 2026, 4:59 a.m. This repo has been linked 1 different CVEs too.

PoC of the CVE-2026-29000

Python

Updated: 1 month, 2 weeks ago
0 stars 1 fork 1 watcher
Born at : May 5, 2026, 9:59 p.m. This repo has been linked 1 different CVEs too.

CVE-2026-29000 PoC: pac4j-jwt PlainJWT-in-JWE authentication bypass.

Python

Updated: 1 month, 2 weeks ago
0 stars 0 fork 0 watcher
Born at : May 3, 2026, 7:20 a.m. This repo has been linked 1 different CVEs too.

An educational deep-dive into CVE-2026-29000

Python

Updated: 1 month, 3 weeks ago
0 stars 0 fork 0 watcher
Born at : April 30, 2026, 5:36 p.m. This repo has been linked 1 different CVEs too.

HackTheBox Principal machine walkthrough — network scanning, directory enumeration and web application analysis

Python

Updated: 1 month, 3 weeks ago
0 stars 0 fork 0 watcher
Born at : April 25, 2026, 9:20 a.m. This repo has been linked 1 different CVEs too.

Proof of Concept for CVE-2026-29000, a vulnerability in pac4j-jwt

Python

Updated: 2 months ago
0 stars 0 fork 0 watcher
Born at : April 17, 2026, 12:51 a.m. This repo has been linked 1 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-29000 vulnerability anywhere in the article.

  • Daily CyberSecurity
Critical 10.0 CVSS Flaw in pac4j-jwt Lets Hackers Forge Admin Tokens

Cybersecurity researchers have uncovered a critical vulnerability in pac4j-jwt, a popular Java-based library used to secure thousands of applications through JSON Web Tokens (JWT). The flaw, tracked a ... Read more

Published Date: Mar 05, 2026 (3 months, 2 weeks ago)

The following table lists the changes that have been made to the CVE-2026-29000 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    Mar. 10, 2026

    Action Type Old Value New Value
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Removed CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
    Removed CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L
  • New CVE Received by [email protected]

    Mar. 04, 2026

    Action Type Old Value New Value
    Added 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.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L
    Added CWE CWE-347
    Added Reference https://www.codeant.ai/security-research/pac4j-jwt-authentication-bypass-public-key
    Added Reference https://www.pac4j.org/blog/security-advisory-pac4j-jwt-jwtauthenticator.html
    Added Reference https://www.vulncheck.com/advisories/pac4j-jwt-jwtauthenticator-authentication-bypass
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.