Vulnerability Details CVE-2026-34950
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 4.2%
CVSS Severity
CVSS v3 Score 9.1