CVE-2026-98531
En el kernel de Linux se ha resuelto la siguiente vulnerabilidad:
ipv6: sr: forzar la longitud exacta del atributo SEG6_ATTR_DST
En seg6_genl_policy, SEG6_ATTR_DST se define con .type = NLA_BINARY y .len = sizeof(struct in6_addr). Para NLA_BINARY, .len solo impone la longitud máxima de la carga útil y permite cargas más cortas (por ejemplo, de 0 bytes). Cuando seg6_genl_set_tunsrc() copia sizeof(struct in6_addr) bytes mediante kmemdup(val, sizeof(*val), GFP_KERNEL), un atributo SEG6_ATTR_DST corto provoca una lectura de 16 bytes fuera de límites más allá de skb->tail, en la memoria de skb->head no inicializada, que se almacena en sdata->tun_src y se filtra al espacio de usuario a través de SEG6_CMD_GET_TUNSRC.
Leer descripción completaMostrar menos
Cambiar SEG6_ATTR_DST en seg6_genl_policy a NLA_POLICY_EXACT_LEN(sizeof(struct in6_addr)) para que la validación genérica de netlink rechace cualquier atributo cuya longitud no sea exactamente sizeof(struct in6_addr) con -ERANGE.
Probado en QEMU contra Linux 7.3.0-rc3 enviando un mensaje de Generic Netlink SEG6_CMD_SET_TUNSRC con un atributo SEG6_ATTR_DST de 0 bytes, seguido de SEG6_CMD_GET_TUNSRC. En el kernel sin corregir, SEG6_CMD_SET_TUNSRC se completa correctamente (err = 0) y SEG6_CMD_GET_TUNSRC filtra 16 bytes de memoria heap del kernel no inicializada (tun_src = 836a61ecc4d25a1042a8d60411cfb378); con este parche aplicado, SEG6_CMD_SET_TUNSRC es rechazado por la validación de la política de netlink con -ERANGE (-34) y tun_src permanece a cero.
Traducción automática del texto original de NVD (en inglés).
CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días
- 0.22 %
- Percentil entre todas las CVEs puntuadas
- 12
- Fecha de la puntuación
- 20/10/2026
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).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
Mostrar las 8 referencias
- https://git.kernel.org/stable/c/050a0aa3c80907b8c60a396b7e04d48d8b1a9e70
- https://git.kernel.org/stable/c/195813bb7324c338eaba0aaa02b18681ee65b670
- https://git.kernel.org/stable/c/209eefebee54c4a5f01d68b61e8ac9881eca2de9
- https://git.kernel.org/stable/c/2d959c75c27f90e9ec489d18ce5ee6b852ad4741
- https://git.kernel.org/stable/c/66bf65fa109326e4c4ddeb0b94093379f72838fd
- https://git.kernel.org/stable/c/6fcfc362344edea745a69f3a705de50b731f3418
- https://git.kernel.org/stable/c/94214cf0a08dd2c5f37aeeea46078d9dfe8e4a0e
- https://git.kernel.org/stable/c/e3ac68c1cdc2535d127b2bfd50c263d16c8e4199
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-98531",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "915d7e5e5930b4f01d0971d93b9b25ed17d221aa",
"lessThan": "050a0aa3c80907b8c60a396b7e04d48d8b1a9e70",
"versionType": "git"
},
{
"status": "affected",
"version": "915d7e5e5930b4f01d0971d93b9b25ed17d221aa",
"lessThan": "209eefebee54c4a5f01d68b61e8ac9881eca2de9",
"versionType": "git"
},
{
"status": "affected",
"version": "915d7e5e5930b4f01d0971d93b9b25ed17d221aa",
"lessThan": "e3ac68c1cdc2535d127b2bfd50c263d16c8e4199",
"versionType": "git"
},
{
"status": "affected",
"version": "915d7e5e5930b4f01d0971d93b9b25ed17d221aa",
"lessThan": "66bf65fa109326e4c4ddeb0b94093379f72838fd",
"versionType": "git"
},
{
"status": "affected",
"version": "915d7e5e5930b4f01d0971d93b9b25ed17d221aa",
"lessThan": "195813bb7324c338eaba0aaa02b18681ee65b670",
"versionType": "git"
},
{
"status": "affected",
"version": "915d7e5e5930b4f01d0971d93b9b25ed17d221aa",
"lessThan": "6fcfc362344edea745a69f3a705de50b731f3418",
"versionType": "git"
},
{
"status": "affected",
"version": "915d7e5e5930b4f01d0971d93b9b25ed17d221aa",
"lessThan": "94214cf0a08dd2c5f37aeeea46078d9dfe8e4a0e",
"versionType": "git"
},
{
"status": "affected",
"version": "915d7e5e5930b4f01d0971d93b9b25ed17d221aa",
"lessThan": "2d959c75c27f90e9ec489d18ce5ee6b852ad4741",
"versionType": "git"
}
],
"programFiles": [
"net/ipv6/seg6.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.10"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.10",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.271",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.222",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.189",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.158",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.112",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.55",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.9",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/ipv6/seg6.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-10-18T16:17:04.653",
"references": [
{
"url": "https://git.kernel.org/stable/c/050a0aa3c80907b8c60a396b7e04d48d8b1a9e70",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/195813bb7324c338eaba0aaa02b18681ee65b670",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/209eefebee54c4a5f01d68b61e8ac9881eca2de9",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/2d959c75c27f90e9ec489d18ce5ee6b852ad4741",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/66bf65fa109326e4c4ddeb0b94093379f72838fd",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/6fcfc362344edea745a69f3a705de50b731f3418",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/94214cf0a08dd2c5f37aeeea46078d9dfe8e4a0e",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/e3ac68c1cdc2535d127b2bfd50c263d16c8e4199",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: sr: enforce exact attribute length for SEG6_ATTR_DST\n\nIn seg6_genl_policy, SEG6_ATTR_DST is defined with .type = NLA_BINARY and\n.len = sizeof(struct in6_addr). For NLA_BINARY, .len only enforces the\nmaximum payload length and permits shorter payloads (e.g., 0 bytes).\nWhen seg6_genl_set_tunsrc() copies sizeof(struct in6_addr) bytes via\nkmemdup(val, sizeof(*val), GFP_KERNEL), a short SEG6_ATTR_DST attribute\ntriggers a 16-byte out-of-bounds read past skb->tail into uninitialized\nskb->head memory, which is stored in sdata->tun_src and leaked back to\nuserspace via SEG6_CMD_GET_TUNSRC.\n\nSwitch SEG6_ATTR_DST in seg6_genl_policy to\nNLA_POLICY_EXACT_LEN(sizeof(struct in6_addr)) so that generic netlink\nvalidation rejects any attribute whose length is not exactly\nsizeof(struct in6_addr) with -ERANGE.\n\nTested in QEMU against Linux 7.3.0-rc3 by sending a SEG6_CMD_SET_TUNSRC\nGeneric Netlink message with a 0-byte SEG6_ATTR_DST attribute followed\nby SEG6_CMD_GET_TUNSRC. On the unfixed kernel, SEG6_CMD_SET_TUNSRC\nsucceeds (err = 0) and SEG6_CMD_GET_TUNSRC leaks 16 bytes of\nuninitialized kernel heap memory (tun_src =\n836a61ecc4d25a1042a8d60411cfb378); with this patch applied,\nSEG6_CMD_SET_TUNSRC is rejected by netlink policy validation with\n-ERANGE (-34) and tun_src remains zeroed."
}
],
"lastModified": "2026-10-19T10:19:08.527",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}