CVE-2026-29000
Received Received - Intake
Authentication Bypass in pac4j-jwt via Encrypted JWT Forgery

Publication date: 2026-03-04

Last updated on: 2026-03-10

Assigner: VulnCheck

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.
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Meta Information
Published
2026-03-04
Last Modified
2026-03-10
Generated
2026-06-16
AI Q&A
2026-03-05
EPSS Evaluated
2026-06-15
NVD
CVE-2026-29000
EUVD
EUVD-2026-9505
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
pac4j pac4j-jwt to 4.5.9 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-347 The product does not verify, or incorrectly verifies, the cryptographic signature for data.
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Executive Summary

The vulnerability exists in pac4j-jwt versions prior to 4.5.9, 5.7.9, and 6.3.3 within the JwtAuthenticator component when processing encrypted JWTs.

It allows remote attackers who have access to the server's RSA public key to create a specially crafted JWE-wrapped PlainJWT containing arbitrary subject and role claims.

This crafted token bypasses signature verification, enabling attackers to authenticate as any user, including administrators.

Impact Analysis

This vulnerability can have severe impacts as it allows attackers to bypass authentication controls.

Attackers can impersonate any user, including privileged administrator accounts, potentially gaining unauthorized access to sensitive data and system functions.

Such unauthorized access can lead to data breaches, system compromise, and loss of trust in the affected application.

Compliance Impact

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Detection Guidance

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Mitigation Strategies

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