CVE-2026-43190

Estado: AnalizadaAlta (8.2)—

In the Linux kernel, the following vulnerability has been resolved:

netfilter: xt_tcpmss: check remaining length before reading optlen

Quoting reporter: In net/netfilter/xt_tcpmss.c (lines 53-68), the TCP option parser reads op[i+1] directly without validating the remaining option length.

Detalles técnicos trazas, registros y código del informe original

  If the last byte of the option field is not EOL/NOP (0/1), the code attempts
  to index op[i+1]. In the case where i + 1 == optlen, this causes an
  out-of-bounds read, accessing memory past the optlen boundary
  (either reading beyond the stack buffer _opt or the
  following payload).

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
Puntuación base: 8.2

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.63%
Percentil entre todas las CVEs puntuadas: 49
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.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access75 %
Impacto principalT1499.004 Application or System Exploitationimpact65 %
Impacto secundarioT1005 Data from Local Systemcollection55 %

Vulnerabilidad remota en netfilter (AV:N, PR:N, UI:N) con lectura fuera de límites en parser TCP. Causa DoS (A:H) e información disclosure (C:L) mediante acceso a memoria del kernel.

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

Filter Network Traffic Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Application Isolation and Sandboxing

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-125

Referencias

JSON original (NVD)

Mostrar

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: xt_tcpmss: check remaining length before reading optlen\n\nQuoting reporter:\n  In net/netfilter/xt_tcpmss.c (lines 53-68), the TCP option parser reads\n op[i+1] directly without validating the remaining option length.\n\n  If the last byte of the option field is not EOL/NOP (0/1), the code attempts\n  to index op[i+1]. In the case where i + 1 == optlen, this causes an\n  out-of-bounds read, accessing memory past the optlen boundary\n  (either reading beyond the stack buffer _opt or the\n  following payload)."
    }
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