CVE-2026-59638

Estado: AnalizadaCrítica (9.3)—

In Bouncy Castle for Java before 1.85, JSSE hostname verifier CN-fallback enabled by default despite documented opt-in. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bctls-fips 1.0.24 (1.0.X series), 2.0.24 (2.0.X series) and 2.1.24 (2.1.X series).

CVSS

Versión: 4.0
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Amber
Puntuación base: 9.3

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.34%
Percentil entre todas las CVEs puntuadas: 26
Fecha de la puntuación: 4/10/2026

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.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access75 %
Impacto principalT1557 Adversary-in-the-Middlecredential access · collection70 %
Impacto secundarioT1090.001 Internal Proxycommand and control65 %

Vulnerabilidad de verificación de certificados (CWE-297) con acceso remoto sin privilegios (AV:N/PR:N) que permite MITM al aceptar CN fallback en JSSE; impacta confidencialidad e integridad de conexiones TLS.

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

Network Segmentation Network Intrusion Prevention Limit Access to Resource Over Network Filter Network Traffic Vulnerability Scanning User Training

Tecnologías afectadas (3)

Bouncycastle — Bc-java Bouncycastle — Bctls-fips Bouncycastle — Bouncy Castle FOR Java LTS

CWE

CWE-297

Referencias

JSON original (NVD)

Mostrar

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