CVE-2026-64538
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix null-ptr-deref in fib6_nh_mtu_change().
fib6_nh_mtu_change() re-fetches idev via __in6_dev_get(arg->dev) and dereferences idev->cnf.mtu6 without a NULL check. addrconf_ifdown() clears dev->ip6_ptr with RCU_INIT_POINTER() after rt6_disable_ip() has released tb6_lock, so the RA-driven MTU walk can observe a NULL idev and oops. The caller rt6_mtu_change_route() guards its own __in6_dev_get(), but this re-fetch is unguarded; nexthop-backed routes survive addrconf_ifdown()'s flush, so the walk still reaches it after ip6_ptr is nulled.
Leer descripción completaMostrar menos
Return 0 when idev is NULL, matching rt6_mtu_change_route() and the fib6_mtu() fix in commit 5ad509c1fdad ("ipv6: Fix null-ptr-deref in fib6_mtu().").
Detalles técnicos trazas, registros y código del informe original
Oops: general protection fault, ... KASAN: null-ptr-deref in range
[0x00000000000002a8-0x00000000000002af]
RIP: 0010:fib6_nh_mtu_change+0x203/0x990
rt6_mtu_change_route+0x141/0x1d0
__fib6_clean_all+0xd0/0x160
rt6_mtu_change+0xb4/0x100
ndisc_router_discovery+0x24b5/0x2cb0
icmpv6_rcv+0x12e9/0x1710
ipv6_rcv+0x39b/0x410CVSS
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: 0.19%
- Percentil entre todas las CVEs puntuadas: 8
- 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).
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/1451deca9896957159f0666520a792c1b861af4f
- https://git.kernel.org/stable/c/302d57ed7872838b40e56a868fb4c7da7da606e9
- https://git.kernel.org/stable/c/46c3b8191aad3d032776bf3bebf03efdf5f4b905
- https://git.kernel.org/stable/c/6428634f7a0b7878144b4925c37856bef3224967
- https://git.kernel.org/stable/c/80600b5d0f3ecb9324120dc95b5e915130f516c5
- https://git.kernel.org/stable/c/b0d0eb13a0441a8ebf4f227843deaf494f1e2c33
- https://git.kernel.org/stable/c/b2c70dd3326809429b709a9c7e9220d29923051a
- https://git.kernel.org/stable/c/d08d019f2f43a6f9a71e81868bbc326b3afaf37b
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
JSON original (NVD)
Mostrar
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"id": "CVE-2026-64538",
"cveTags": [],
"metrics": {},
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"published": "2026-07-27T21:17:06.130",
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],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: Fix null-ptr-deref in fib6_nh_mtu_change().\n\nfib6_nh_mtu_change() re-fetches idev via __in6_dev_get(arg->dev) and\ndereferences idev->cnf.mtu6 without a NULL check. addrconf_ifdown()\nclears dev->ip6_ptr with RCU_INIT_POINTER() after rt6_disable_ip() has\nreleased tb6_lock, so the RA-driven MTU walk can observe a NULL idev and\noops. The caller rt6_mtu_change_route() guards its own __in6_dev_get(),\nbut this re-fetch is unguarded; nexthop-backed routes survive\naddrconf_ifdown()'s flush, so the walk still reaches it after ip6_ptr is\nnulled.\n\nReturn 0 when idev is NULL, matching rt6_mtu_change_route() and the\nfib6_mtu() fix in commit 5ad509c1fdad (\"ipv6: Fix null-ptr-deref in\nfib6_mtu().\").\n\n Oops: general protection fault, ... KASAN: null-ptr-deref in range\n [0x00000000000002a8-0x00000000000002af]\n RIP: 0010:fib6_nh_mtu_change+0x203/0x990\n rt6_mtu_change_route+0x141/0x1d0\n __fib6_clean_all+0xd0/0x160\n rt6_mtu_change+0xb4/0x100\n ndisc_router_discovery+0x24b5/0x2cb0\n icmpv6_rcv+0x12e9/0x1710\n ipv6_rcv+0x39b/0x410"
}
],
"lastModified": "2026-09-08T09:18:19.810",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}