CVE-2026-34950: Nearform Fast-Jwt

Critical severity, CVSS 9.1. EPSS: 0.3% chance of exploitation in the next 30 days.

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.

Affected products

• Nearform Fast-Jwt: before 6.2.0 (fixed in 6.2.0)

Published 2026-04-06. Last modified 2026-06-17.