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CVE-2026-34950

Estado: AnalizadaCrítica (9.1)—

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

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

JWT algorithm confusion permite autenticarse como usuario arbitrario (T1078) o manipular tokens. AV:N/PR:N indica red sin privilegios (T1190). Regresión de CVE-2023-48223 confirma impacto.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Privileged Account ManagementNetwork SegmentationApplication Developer GuidanceActive Directory ConfigurationVulnerability ScanningUser Training

Tecnologías afectadas (1)

Nearform — Fast-jwt

CWE

Referencias

JSON original (NVD)

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