CVE-2026-34950

CRITICAL EPSS 14.3%
Published Apr 6, 20262mo ago · Modified Jun 17, 20262w ago
9.1 CVSS 3.1
Critical
Find Similar
Published Apr 6, 2026 2mo ago
Last Modified Jun 17, 2026 2w ago

Description

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 algorithm confusion attack that CVE-2023-48223 patched.

CVSS Details

Base Score
9.1
Exploitability
3.9
Impact
5.2
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability None

Threat Intelligence

EPSS Exploit Probability
14.3% percentile
Exploit & Patch Status
Public Exploit Known
No Patch Available

Weaknesses 1

CWE-327

Affected Products 1

VendorProductVersionRange
nearformfast-jwt* <6.2.0

References 1

  • github.com https://github.com/nearform/fast-jwt/security/advisories/GHSA-mvf2-f6gm-w987
    ExploitVendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.