What is the CVSS score of CVE-2026-29000?

CVE-2026-29000 has a CVSS 4.0 base score of 9.3 (Critical). CVSS vector: 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. EPSS exploitation probability: 0.1%.

Is there a public PoC exploit available for CVE-2026-29000?

Yes, a public proof-of-concept exploit is available for CVE-2026-29000. Prioritise patching immediately. EPSS: 0.1%.

How to fix or mitigate CVE-2026-29000?

Within 24 hours: Inventory all applications using pac4j-jwt and identify those running versions ≤4.5.9; implement network segmentation to restrict access to affected services. Within 7 days: Apply the upgrade to pac4j-jwt 4.5.10 or later once released by the vendor; conduct regression testing in staging environments. Within 30 days: Complete production deployment of patched versions; perform security audit of JWT token handling and review access logs for signs of exploitation.

Jwt Attack CVE-2026-29000

CRITICAL

Improper Verification of Cryptographic Signature (CWE-347)

2026-03-04 disclosure@vulncheck.com

GHSA-pm7g-w2cf-q238

Authentication Bypass Jwt Attack

9.3

CVSS 4.0 · Vendor: vulncheck

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Obtain server's RSA public key
Delivery

Craft JWE-wrapped PlainJWT with admin claims
Exploit

Submit forged token to JwtAuthenticator
Execution

Bypass signature verification
Impact

Authenticate as administrator

Vulnerability Assessment

Weakness	CWE CWE-347 OWASP Top 10:2025 A04:2025 - Cryptographic Failures ASVS 5.0 V11 - Cryptography Signature verification
Exploitation Conditions	pac4j-jwt versions prior to 4.5.9, 5.7.9, or 6.3.3 with JwtAuthenticator processing encrypted JWTs. Attacker must possess the server's RSA public key (typically public information). No authentication or special user interaction required.
Impact	CVSS 9.1.
Exploit ScenarioDerived	Forge JWT tokens to bypass authentication.

Act Now Prioritize within 24-48h. Why: CRITICAL severity + public POC available.

Patch available 0.1% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAIv1 – Mar 12, 2026

JWT authentication bypass in pac4j-jwt before 4.5.9/5.7.9/6.3.3 when processing encrypted JWTs. PoC available.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 22:05 CVSS 9.1

JWT auth bypass in pac4j-jwt.

RemediationAI

Update pac4j-jwt.

Affected Packages

maven org.pac4j:pac4j-jwt fix: 4.5.9, 5.7.9, 6.3.3

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in maven

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

CWE-347 improper signature verification.

Know when Jwt Attack gets its next vulnerability

Watch products and get an email when something new is published
Check this CVE against your own stack and servers
Exploit and PoC references, threat intelligence from 22 sources

Continue with Google Continue with GitHub

No credit card · 7-day full trial

Severity by source

Vendor (vulncheck) PRIMARY 9.3 CRITICAL

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

Primary rating from Vendor (vulncheck) · only source for this CVE.

CVSS VectorVendor: vulncheck

Attack Vector

Network

Attack Complexity

Low

Attack Requirements

None

Privileges Required

None

User Interaction

None

Vulnerable system: Confidentiality

High

Vulnerable system: Integrity

High

Vulnerable system: Availability

None

Subsequent system: Confidentiality

None

Subsequent system: Integrity

None

Subsequent system: Availability

None

Lifecycle Timeline

CVSS changed

Apr 16, 2026 - 16:22 NVD

9.1 (CRITICAL) 9.3 (CRITICAL)

Patch released

Mar 31, 2026 - 21:13 nvd

Patch available

PoC Detected

Mar 10, 2026 - 20:16 vuln.today

Public exploit code

CVE Published

Mar 04, 2026 - 22:16 nvd

CRITICAL 9.1

DescriptionCVE.org

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.

Executive ViewAI

Why It Matters

A critical vulnerability in pac4j-jwt (versions ≤4.5.9) allows attackers to bypass JWT signature verification, potentially enabling unauthorized access to applications that depend on this library for authentication. Organizations using affected versions face immediate risk of authentication bypass and unauthorized data access until remediation is completed.

Business Impact: Severe

Compensating Controls

Disable JWT-based authentication where possible and switch to alternative authentication mechanisms (OAuth 2.0, SAML, mutual TLS); implement strict WAF rules to validate JWT token structure and reject malformed tokens; enforce network segmentation to limit lateral movement if tokens are compromised; deploy enhanced logging and monitoring on authentication endpoints to detect signature validation failures; require additional factors of authentication (MFA) to reduce impact of JWT bypass; monitor vendor advisories and pac4j GitHub for patch availability and apply immediately upon release.

Threat Intelligence Overview

EPSS Score

0.1%

Top 74% exploitable

Exploit

POC

Public exploit code exists

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity CRITICAL

CISA KEV No

Public POC Yes

EPSS 0.1%

Patch available Yes

Active threat No

Deciding rule

CRITICAL severity + public POC available

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Out-of-Cycle

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact

Very High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +46

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Authentication Bypass CRITICAL

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

More in Jwt Attack

View all

CVE-2013-3900 MEDIUM Act Now

5.5 Dec 11

Why is Microsoft republishing a CVE from 2013? We are republishing CVE-2013-3900 in the Security Update Guide to update

CVE-2026-48558 CRITICAL Act Now POC

9.5 Jun 12

Authentication bypass in SimpleHelp 5.5.15 and prior (plus 6.0 pre-release builds) allows remote unauthenticated attacke

CVE-2026-5430 CRITICAL Act Now POC

10.0 Aug 06

Authentication bypass in WSO2 API Manager and related components (Universal Gateway, Traffic Manager, API Control Plane,

CVE-2025-59718 CRITICAL Emergency

9.8 Dec 09

Authentication bypass in Fortinet FortiOS, FortiProxy, and FortiSwitchManager allows unauthenticated remote attackers to

CVE-2025-25291 CRITICAL Act Now POC

9.3 Mar 12

ruby-saml provides security assertion markup language (SAML) single sign-on (SSO) for Ruby. Rated critical severity (CVS

CVE-2026-47304 CRITICAL Act Now POC

9.8 Jul 14

Security feature bypass in Microsoft .NET (shipped via Visual Studio 2022 17.12/17.14 and Visual Studio 2026 18.7) lets

CVE-2025-25292 CRITICAL Act Now POC

9.3 Mar 12

ruby-saml provides security assertion markup language (SAML) single sign-on (SSO) for Ruby. Rated critical severity (CVS

CVE-2022-25898 CRITICAL Act Now POC

9.8 Jul 01

The package jsrsasign before 10.5.25 are vulnerable to Improper Verification of Cryptographic Signature when JWS or JWT

CVE-2026-107722 CRITICAL Act Now POC

9.8 Oct 08

Authentication and authorization bypass in fast-jwt 6.2.0 through 6.2.4 (npm, NearForm) lets a remote, unauthenticated a

CVE-2024-42004 CRITICAL Act Now POC

9.8 Dec 18

A library injection vulnerability exists in Microsoft Teams (work or school) 24046.2813.2770.1094 for macOS. Rated criti

CVE-2024-41145 CRITICAL Act Now POC

9.8 Dec 18

A library injection vulnerability exists in the WebView.app helper app of Microsoft Teams (work or school) 24046.2813.27

CVE-2024-41138 CRITICAL Act Now POC

9.8 Dec 18

A library injection vulnerability exists in the com.microsoft.teams2.modulehost.app helper app of Microsoft Teams (work

Same weakness CWE-347 – Improper Verification of Cryptographic Signature

View all

CVE-2025-47827 MEDIUM POC

4.6

Same technique Authentication Bypass

View all

CVE-2015-3306 CRITICAL POC

10.0

CVE-2023-22515 CRITICAL POC

9.8

CVE-2012-4681 CRITICAL POC

9.8

CVE-2013-2465 CRITICAL POC

9.8

CVE-2011-3544 CRITICAL POC

9.8

CVE-2022-40684 CRITICAL POC

9.8

CVE-2025-61882 CRITICAL POC

9.8

CVE-2024-0012 CRITICAL POC

9.3

References

Advisories & patches

ADVISORY https://vuldb.com/?id.348847 REF https://www.codeant.ai/security-research/pac4j-jwt-authentication-bypass-public-key REF https://www.pac4j.org/blog/security-advisory-pac4j-jwt-jwtauthenticator.html REF https://www.vulncheck.com/advisories/pac4j-jwt-jwtauthenticator-authentication-bypass

Search Externally

GitHub PoC

Exploit-DB PacketStorm Snyk Rapid7 Nuclei Templates Trickest PoC

Back