---
cve: "CVE-2026-29000"
severity: "CRITICAL"
cvss: 9.3
epss: "5.9%"
vendor: "pac4j"
kev: false
exploited: false
published: "2026-03-04 22:16:18"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-03T01:58:03+02:00"
---

# CVE-2026-29000

> 9.3 CRITICAL

## Beschreibung

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-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- 6ef35c29ee47726744dd4181b88456684f5efbf9 (Commit)
- 244459565b06f0d9fa3f2526890ed79a36bfe169 (Commit)

## Referenzen

- <https://www.pac4j.org/blog/security-advisory-pac4j-jwt-jwtauthenticator.html>
- <https://www.codeant.ai/security-research/pac4j-jwt-authentication-bypass-public-key>
- <https://www.vulncheck.com/advisories/pac4j-jwt-jwtauthenticator-authentication-bypass>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-29000) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_