CVE-2026-23455

Estado: ModificadaCrítica (9.1)—

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

netfilter: nf_conntrack_h323: check for zero length in DecodeQ931()

In DecodeQ931(), the UserUserIE code path reads a 16-bit length from the packet, then decrements it by 1 to skip the protocol discriminator byte before passing it to DecodeH323_UserInformation(). If the encoded length is 0, the decrement wraps to -1, which is then passed as a large value to the decoder, leading to an out-of-bounds read.

Add a check to ensure len is positive after the decrement.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Puntuación base: 9.1

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 1.34%
Percentil entre todas las CVEs puntuadas: 70
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 access85 %
Impacto principalT1005 Data from Local Systemcollection90 %

Vulnerabilidad en kernel Linux (netfilter) accesible remotamente sin autenticación. Out-of-bounds read permite lectura de memoria del kernel. CVSS AV:N, PR:N, UI:N; CWE-125 (boundary condition read).

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

Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Filter Network Traffic 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: nf_conntrack_h323: check for zero length in DecodeQ931()\n\nIn DecodeQ931(), the UserUserIE code path reads a 16-bit length from\nthe packet, then decrements it by 1 to skip the protocol discriminator\nbyte before passing it to DecodeH323_UserInformation(). If the encoded\nlength is 0, the decrement wraps to -1, which is then passed as a\nlarge value to the decoder, leading to an out-of-bounds read.\n\nAdd a check to ensure len is positive after the decrement."
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      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnetfilter: nf_conntrack_h323: comprobación de longitud cero en DecodeQ931()\n\nEn DecodeQ931(), la ruta de código UserUserIE lee una longitud de 16 bits del paquete, luego la decrementa en 1 para omitir el byte discriminador del protocolo antes de pasarla a DecodeH323_UserInformation(). Si la longitud codificada es 0, el decremento se ajusta a -1, que luego se pasa como un valor grande al decodificador, lo que lleva a una lectura fuera de límites.\n\nSe añade una comprobación para asegurar que 'len' sea positivo después del decremento."
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