VULNERABILITY INTELLIGENCE

CVE-2026-34950

CVSS score9.1 CRITICAL
EPSS probability0.24%
CISA KEVNot currently listed
Published2026-04-06
Last modified2026-10-26
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

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.

Weakness classification

  • security-advisories@github.com: CWE-327

Primary references