CVE-2026-46195
Estado: ModificadaCrítica (9.8)—
In the Linux kernel, the following vulnerability has been resolved:
smb: client: validate dacloffset before building DACL pointers
parse_sec_desc(), build_sec_desc(), and the chown path in id_mode_to_cifs_acl() all add the server-supplied dacloffset to pntsd before proving a DACL header fits inside the returned security descriptor.
On 32-bit builds a malicious server can return dacloffset near U32_MAX, wrap the derived DACL pointer below end_of_acl, and then slip past the later pointer-based bounds checks. build_sec_desc() and id_mode_to_cifs_acl() can then dereference DACL fields from the wrapped pointer in the chmod/chown rewrite paths.
Leer descripción completaMostrar menos
Validate dacloffset numerically before building any DACL pointer and reuse the same helper at the three DACL entry points.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Puntuación base: 9.8
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.68%
- Percentil entre todas las CVEs puntuadas: 51
- 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.
- Explotación
T1190Exploit Public-Facing Applicationinitial access85 %
Vulnerabilidad en cliente SMB del kernel Linux accesible remotamente sin autenticación (AV:N/PR:N) que permite a un servidor malicioso enviar dacloffset manipulado para causar desbordamiento de buffer (CWE-787) y ejecutar código. La explotación de un cliente de red expuesto a un servidor no confiabl
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
Tecnologías afectadas (1)
CWE
- CWE-476
- CWE-787
Referencias
- https://git.kernel.org/stable/c/3b1ddba19e77ee35241cd27f16dc3e8d14e08db7
- https://git.kernel.org/stable/c/5de2665e913a10ad70aaeecf736b97276e83d995
- https://git.kernel.org/stable/c/8bd07e417b6bda67e317920584e48cb6ee442a8a
- https://git.kernel.org/stable/c/ba7f71b6161c0943dafc367565e5843d16b7d505
- https://git.kernel.org/stable/c/c688f3ed73d31943334ad2139cb02ec49664322a
- https://git.kernel.org/stable/c/f98b48151cc502ada59d9778f0112d21f2586ca3
- https://git.kernel.org/stable/c/f9dc3be8f403c1216df73e57221f44b045e7ee0b
- https://access.redhat.com/errata/RHSA-2026:21556
- https://access.redhat.com/errata/RHSA-2026:21706
- https://access.redhat.com/errata/RHSA-2026:21745
- https://access.redhat.com/security/cve/CVE-2026-46195
- https://bugzilla.redhat.com/show_bug.cgi?id=2482606
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46195.json
JSON original (NVD)
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