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Home / Vulnerability Intelligence / CVE-2026-34950

CVE-2026-34950 - Vulnerability Analysis

CriticalCVSS: 9.1

Last Updated: April 7, 2026

fast-jwt - Authentication Bypass

Published: April 6, 2026Updated: April 7, 2026Remote Exploitable

Overview

fast-jwt <= 6.1.0 contains a JWT algorithm confusion vulnerability caused by improper regex anchoring in publicKeyPemMatcher, letting attackers bypass algorithm restrictions, exploit requires crafted JWT with leading whitespace.

Severity & Score

Severity: Critical
CVSS Score: 9.1
EPSS Score: 2.1%(Probability of exploitation in next 30 days)

Impact

Attackers can bypass JWT algorithm restrictions, potentially allowing unauthorized access or privilege escalation.

Mitigation

Update to a version later than 6.1.0 or the latest available version.

Social Media Activity(2 posts)

TheHackerWire
TheHackerWire
@thehackerwire
Apr 6, 2026

šŸ”“ CVE-2026-34950 - Critical (9.1) fast-jwt provides fast JSON Web Token (JWT) implementation. In 6.1.0 and earlier, the publicKeyPemMatcher regex in fast-jwt/src/crypto.js uses a ^ anchor that is defeated by any leading whitespace in the key string, re-enabling the exact same JWT ... šŸ”— https://www.thehackerwire.com/vulnerability/CVE-2026-34950/ #CVE #vulnerability #infosec #cybersecurity #security #Tenda #patchstack

View original post
TheHackerWire
TheHackerWire
@thehackerwire
Apr 6, 2026

šŸ”“ CVE-2026-34950 - Critical (9.1) fast-jwt provides fast JSON Web Token (JWT) implementation. In 6.1.0 and earlier, the publicKeyPemMatcher regex in fast-jwt/src/crypto.js uses a ^ anchor that is defeated by any leading whitespace in the key string, re-enabling the exact same JWT ... šŸ”— https://www.thehackerwire.com/vulnerability/CVE-2026-34950/ #CVE #vulnerability #infosec #cybersecurity #security #Tenda #patchstack

View original post

Details

CVE ID
CVE-2026-34950
Severity
Critical
CVSS Score
9.1
Type
broken_authentication
Status
unconfirmed
EPSS
2.1%
Social Posts
2

CWE

  • CWE-327

CVSS Metrics

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

EPSS Score

2.1%Probability of exploitation in the next 30 days