CVE-2026-64542
In the Linux kernel, the following vulnerability has been resolved:
ipv6: ndisc: fix NULL deref in accept_untracked_na()
accept_untracked_na() re-fetches the inet6_dev with __in6_dev_get(dev) and dereferences idev->cnf.accept_untracked_na without a NULL check, even though its only caller ndisc_recv_na() already fetched and NULL-checked idev for the same device.
Both reads of dev->ip6_ptr run in the same RCU read-side critical section, but a concurrent addrconf_ifdown() can clear dev->ip6_ptr between them: lowering the MTU below IPV6_MIN_MTU calls addrconf_ifdown() without the synchronize_net() that orders the unregister path, so the re-fetch returns NULL and oopses:
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It is reachable by an unprivileged user via a network namespace.
Pass the caller's already validated idev instead of re-fetching it; the idev stays alive for the whole RCU critical section, so it is safe even after dev->ip6_ptr has been cleared.
Detalles técnicos trazas, registros y código del informe original
BUG: KASAN: null-ptr-deref in ndisc_recv_na (net/ipv6/ndisc.c:974) Read of size 4 at addr 0000000000000364 Call Trace: <IRQ> ndisc_recv_na (net/ipv6/ndisc.c:974) icmpv6_rcv (net/ipv6/icmp.c:1193) ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:479) ip6_input_finish (net/ipv6/ip6_input.c:534) ip6_input (net/ipv6/ip6_input.c:545) ip6_mc_input (net/ipv6/ip6_input.c:635) ipv6_rcv (net/ipv6/ip6_input.c:351) </IRQ>
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: 0.17%
- Percentil entre todas las CVEs puntuadas: 6
- Fecha de la puntuación: 5/10/2026
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/160d3f0d7a556ceae505dcab521a37057b4ce28f
- https://git.kernel.org/stable/c/62c719203cb521b64fab74da94a81bdde5c18808
- https://git.kernel.org/stable/c/63d1c23764de2309cedbb779c75188d257a09d9b
- https://git.kernel.org/stable/c/a6450f7cfae57b382cbaf66a577765c9a88b3c58
- https://git.kernel.org/stable/c/d186e942365acece7c56d39da05dd63bf95b280a
- https://git.kernel.org/stable/c/e5ba3017e46f275ad347e762e8eecacec5efa41d
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-64542",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"programFiles": [
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],
"defaultStatus": "unaffected"
},
{
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"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.0"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.148",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver",
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},
{
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/ipv6/ndisc.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-07-27T21:17:06.730",
"references": [
{
"url": "https://git.kernel.org/stable/c/160d3f0d7a556ceae505dcab521a37057b4ce28f",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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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\nipv6: ndisc: fix NULL deref in accept_untracked_na()\n\naccept_untracked_na() re-fetches the inet6_dev with __in6_dev_get(dev)\nand dereferences idev->cnf.accept_untracked_na without a NULL check,\neven though its only caller ndisc_recv_na() already fetched and\nNULL-checked idev for the same device.\n\nBoth reads of dev->ip6_ptr run in the same RCU read-side critical\nsection, but a concurrent addrconf_ifdown() can clear dev->ip6_ptr\nbetween them: lowering the MTU below IPV6_MIN_MTU calls addrconf_ifdown()\nwithout the synchronize_net() that orders the unregister path, so the\nre-fetch returns NULL and oopses:\n\n BUG: KASAN: null-ptr-deref in ndisc_recv_na (net/ipv6/ndisc.c:974)\n Read of size 4 at addr 0000000000000364\n Call Trace:\n <IRQ>\n ndisc_recv_na (net/ipv6/ndisc.c:974)\n icmpv6_rcv (net/ipv6/icmp.c:1193)\n ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:479)\n ip6_input_finish (net/ipv6/ip6_input.c:534)\n ip6_input (net/ipv6/ip6_input.c:545)\n ip6_mc_input (net/ipv6/ip6_input.c:635)\n ipv6_rcv (net/ipv6/ip6_input.c:351)\n </IRQ>\n\nIt is reachable by an unprivileged user via a network namespace.\n\nPass the caller's already validated idev instead of re-fetching it; the\nidev stays alive for the whole RCU critical section, so it is safe even\nafter dev->ip6_ptr has been cleared."
}
],
"lastModified": "2026-08-19T17:20:15.523",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}