pac4j pac4j-jwt up to 4.5.8/5.7.8/6.3.2 signature verification

CVSS Meta Temp Score
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CTI Interest Score
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8.0$0-$5k0.00

Summaryinfo

A vulnerability identified as critical has been detected in pac4j pac4j-jwt up to 4.5.8/5.7.8/6.3.2. This issue affects some unknown processing. This manipulation causes signature verification. This vulnerability is tracked as CVE-2026-29000. The attack is possible to be carried out remotely. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in pac4j pac4j-jwt up to 4.5.8/5.7.8/6.3.2. It has been declared as critical. Affected by this vulnerability is some unknown functionality. The manipulation with an unknown input leads to a signature verification vulnerability. The CWE definition for the vulnerability is CWE-347. The product does not verify, or incorrectly verifies, the cryptographic signature for data. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at pac4j.org. This vulnerability is known as CVE-2026-29000 since 03/03/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 303225 (Pac4J JWT < 4.5.9 / 5.x < 5.7.9 / 6.x < 6.3.3 Authentication Bypass (CVE-2026-29000) (Direct Check)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.5.9, 5.7.9 or 6.3.3 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (303225). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 8.2
VulDB Meta Temp Score: 8.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 9.1
CNA Vector (VulnCheck): 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Signature verification
CWE: CWE-347 / CWE-345
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 303225
Nessus Name: Pac4J JWT < 4.5.9 / 5.x < 5.7.9 / 6.x < 6.3.3 Authentication Bypass (CVE-2026-29000) (Direct Check)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: pac4j-jwt 4.5.9/5.7.9/6.3.3

Timelineinfo

03/03/2026 CVE reserved
03/05/2026 +2 days Advisory disclosed
03/05/2026 +0 days VulDB entry created
03/23/2026 +18 days VulDB entry last update

Sourcesinfo

Advisory: pac4j.org
Status: Confirmed

CVE: CVE-2026-29000 (🔒)
GCVE (CVE): GCVE-0-2026-29000
GCVE (VulDB): GCVE-100-348847

Entryinfo

Created: 03/05/2026 02:42
Updated: 03/23/2026 04:21
Changes: 03/05/2026 02:42 (74), 03/11/2026 04:41 (11), 03/23/2026 04:21 (2)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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