CVE-2026-34950CRITICAL 9.1EPSS p14.2%
CVE-2026-34950CVE-2026-34950
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.
Scoring
| CVSS 3.1 | 9.1 (CRITICAL) |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| EPSS | 0.24% probability of exploitation · percentile 14.2% · 2026-06-19T12:03:05Z |
| Published | 2026-04-06 |
| Last modified | 2026-04-22 |
Underlying weaknesses· 1
References
1
| Type | Target | Confidence | Tier |
|---|---|---|---|
| Weakness | Use of a Broken or Risky Cryptographic Algorithmcwe-327 | 0% | live |
Related by meaning· 6
Nearest entities by semantic similarity across the cs-graph corpus.