CVE-2026-40420

Estado: ModificadaAlta (8.8)—

Use after free in Microsoft Office allows an authorized attacker to elevate privileges locally.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Puntuación base: 8.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.30%
Percentil entre todas las CVEs puntuadas: 21
Fecha de la puntuación: 6/10/2026

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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation95 %
Impacto principalT1078 Valid Accountsstealth · persistence · privilege escalation · initial access85 %
Impacto secundarioT1548 Abuse Elevation Control Mechanismprivilege escalation80 %

Use-after-free local (AV:L, PR:L, UI:N) permite escalada de privilegios en Office. Attacker autorizado logra elevar permisos y obtener acceso con privilegios más altos (scope changed, C:H, I:H, A:H).

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

User Account Management Privileged Account Management Execution Prevention Update Software Application Developer Guidance Active Directory Configuration

Tecnologías afectadas (3)

Microsoft — 365 Apps Microsoft — Office Microsoft — Office Long Term Servicing Channel

CWE

CWE-284

Referencias

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40420

JSON original (NVD)

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