CVE-2026-80731
Estado: RecibidaAlta (7.8)—
In the Linux kernel, the following vulnerability has been resolved:
net: remove CAP_SYS_RAWIO zero-padding in dev_validate_header
dev_validate_header() reads dev->hard_header_len directly when zero-padding short link layer headers for CAP_SYS_RAWIO holders:
Packet send paths call dev_validate_header() on skbs whose headroom was allocated from an earlier hard_header_len read. If the device is reconfigured so that dev->hard_header_len increases before validation, the memset writes past the reserved buffer, an out-of-bounds write.
This out-of-bounds write is masked in some SOCK_RAW paths today because the same concurrent increase can first make skb_push() exceed the reserved headroom and trigger skb_under_panic().
Leer descripción completaMostrar menos
Remove the zero-padding branch before making those hard_header_len reads consistent, so the snapshot fixes do not turn a loud panic into a silent overwrite.
This path is only reached for variable length L2 protocols, where len < hard_header_len but len >= min_header_len. No remaining in-tree variable length L2 protocol implements header_ops->validate, and the CAP_SYS_RAWIO bypass that zero-pads and accepts short headers has no real value beyond allowing testing of intentionally malformed input.
Drop the CAP_SYS_RAWIO branch. The remaining reads of dev->hard_header_len in dev_validate_header() are comparisons only and have no memory safety impact.
Detalles técnicos trazas, registros y código del informe original
if (capable(CAP_SYS_RAWIO)) {
memset(ll_header + len, 0, dev->hard_header_len - len);
return true;
}CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Puntuación base: 7.8
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.14%
- Percentil entre todas las CVEs puntuadas: 3
- 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
T1068Exploitation for Privilege Escalationprivilege escalation85 % - Impacto principal
T1565.001Stored Data Manipulationimpact75 % - Impacto secundario
T1499.004Application or System Exploitationimpact65 %
Vulnerabilidad en kernel Linux (AV:L, PR:L) que permite escritura fuera de límites (out-of-bounds write) al reconfigurar hard_header_len. Escalada de privilegios local y corrupción de memoria con potencial DoS.
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)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
- https://git.kernel.org/stable/c/3b9a324e646d3657a8d9806dfbfe4f3e4066e882
- https://git.kernel.org/stable/c/53fd7f912c0877647d6a1e1877f5ea8535ee0b4a
- https://git.kernel.org/stable/c/74e035f07f53feca09e2352e77fccb09cad5e208
- https://git.kernel.org/stable/c/8fc9816404166a90ed8d544dc52482fafffb6d9f
- https://git.kernel.org/stable/c/99df6b7a713f96eda206680d100b76e15f9d9b69
- https://git.kernel.org/stable/c/b0f92a5731dc82556a9ae005cc35f71ab136307b
- https://git.kernel.org/stable/c/dbb30dc943a93e083f1e531bfdc6779e57de40d0
- https://git.kernel.org/stable/c/fa6d98dd925e72fc028b26a0cbbff9d2f0601ff6
- https://git.kernel.org/stable/c/fc902f52a02298c7432b2334c0c82a2885a1a8b6
JSON original (NVD)
Mostrar
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"id": "CVE-2026-80731",
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{
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"version": "3.1",
"baseScore": 7.8,
"attackVector": "LOCAL",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "LOW",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.9,
"exploitabilityScore": 1.8
}
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"published": "2026-09-03T13:06:11.707",
"references": [
{
"url": "https://git.kernel.org/stable/c/3b9a324e646d3657a8d9806dfbfe4f3e4066e882",
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: remove CAP_SYS_RAWIO zero-padding in dev_validate_header\n\ndev_validate_header() reads dev->hard_header_len directly when\nzero-padding short link layer headers for CAP_SYS_RAWIO holders:\n\n if (capable(CAP_SYS_RAWIO)) {\n memset(ll_header + len, 0, dev->hard_header_len - len);\n return true;\n }\n\nPacket send paths call dev_validate_header() on skbs whose headroom was\nallocated from an earlier hard_header_len read. If the device is\nreconfigured so that dev->hard_header_len increases before validation,\nthe memset writes past the reserved buffer, an out-of-bounds write.\n\nThis out-of-bounds write is masked in some SOCK_RAW paths today because\nthe same concurrent increase can first make skb_push() exceed the\nreserved headroom and trigger skb_under_panic(). Remove the zero-padding\nbranch before making those hard_header_len reads consistent, so the\nsnapshot fixes do not turn a loud panic into a silent overwrite.\n\nThis path is only reached for variable length L2 protocols, where\nlen < hard_header_len but len >= min_header_len. No remaining in-tree\nvariable length L2 protocol implements header_ops->validate, and the\nCAP_SYS_RAWIO bypass that zero-pads and accepts short headers has no\nreal value beyond allowing testing of intentionally malformed input.\n\nDrop the CAP_SYS_RAWIO branch. The remaining reads of\ndev->hard_header_len in dev_validate_header() are comparisons only and\nhave no memory safety impact."
}
],
"lastModified": "2026-09-04T05:17:13.583",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}