CVE-2026-29000Critical· 9.1▾ AbyssalPoC available

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

▾ Abyssal zone — Critical with a public exploit or in-the-wild use

Depth score63/ 100 · Elevated

impact 50.1 · likelihood 1.2 · exploitation 12

⚡ Agent-ready:Raw markdown ↗JSON ↗

Proof of concept

A public proof-of-concept already exists for this vulnerability — see Exploit availability below.

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Published

Mar 4, 2026

Updated

Oct 8, 2026

CVSS

9.1

Vendor

pac4j

Product

pac4j-jwt

CWE

CWE-347

Depth score

63 · Elevated

EPSS

6.1% · p93

Platforms

—

Source

NVD

Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Exploit availability

Public exploit / PoC code seen in 1 source. Availability, not in-the-wild use.

checked 2026-10-27

GitHub PoCs

22 public repositories

CISA SSVC

decided 2026-03-07

Exploitation: poc
Automatable: yes
Technical impact: total

Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.

EPSS history

Exploit-prediction probability, daily snapshots since Oct 8.

0.5% → 6.1%▲ 5.6%

Timeline

Disclosure to exploitation, from the record and what we observed since indexing it.

5 events · 238 days

Mar 4, 2026Published
Disclosed via NVD
Oct 8, 2026Record revised
Last analysed / modified upstream
Oct 8, 2026EPSS first tracked
0.5%
Oct 26, 2026EPSS peak
0.5% → 6.1%
Oct 27, 2026Public exploit observed
22 GitHub repos (last check)

pac4j CWE-347 #nvd #cve.org #exploit-available

Affected

pac4j-jwt >= 4.0 < 4.5.9
pac4j-jwt >= 5.0 < 5.7.9
pac4j-jwt >= 6.0 < 6.3.3

Full technical detail▾

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.

References

Change history

Field changes observed since this record was first indexed.

Oct 27, 2026EPSS 1% → 6%

Related vulnerabilities

Connected by shared product, vendor, weakness, or advisory.

#nvd#cve.org#exploit-available

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