CVE-2026-8711

Estado: AnalizadaCrítica (9.2)—

NGINX JavaScript has a vulnerability when the js_fetch_proxy directive is configured with at least one client-controlled NGINX variable (for example, $http_*, $arg_*, $cookie_*) and a location invoking the ngx.fetch() operation from NGINX JavaScript. An unauthenticated attacker can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR.

Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

CVSS

Versión: 4.0
Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/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:X
Puntuación base: 9.2

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.79%
Percentil entre todas las CVEs puntuadas: 55
Fecha de la puntuación: 5/10/2026

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 access95 %
Impacto principalT1059 Command and Scripting Interpreterexecution85 %
Impacto secundarioT1499.004 Application or System Exploitationimpact75 %

Vulnerabilidad en aplicación NGINX expuesta (js_fetch_proxy con variables controlables). Vector CVSS AV:N/PR:N permite explotación remota sin autenticación. Heap buffer overflow puede causar DoS o RCE si ASLR está deshabilitado.

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 Management Filter Network Traffic Vulnerability Scanning Restrict Web-Based Content Network Segmentation Limit Software Installation

Tecnologías afectadas (1)

F5 — NJS

CWE

CWE-122

Referencias

https://my.f5.com/manage/s/article/K000161307

JSON original (NVD)

Mostrar

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