CVE-2026-97984
Estado: RecibidaSin puntuar—
In the Linux kernel, the following vulnerability has been resolved:
net: ipv6: Fix UDP length overflow with PMTU discover and big MTU
This commit bounds cork->base.fragsize to IP6_MAX_MTU for UDP sockets to avoid a possible overflow of UDP length that triggers a WARN in udp_set_len_short when setsockopt IPV6_MTU_DISCOVER is set to IPV6_PMTUDISC_DO or IPV6_PMTUDISC_PROBE, and a large packet is sent over a netdev with an unusually large MTU.
Steps to reproduce (included in the new selftest):
To avoid breaking sending UDP jumbograms over raw IPv6 sockets, limit the change to UDP sockets only.
The original overflow bug with IPv6 and IPV6_PMTUDISC_DO seems to predate git history (verified reproduction on 2.6.21), was fixed later, and then reappeared in commit 427faee167bc ("net: ipv6: introduce ip6_dst_mtu_maybe_forward"), which is chosen as the Fixes tag here.
Leer descripción completaMostrar menos
The overflow with IPV6_PMTUDISC_PROBE reproduces since its introduction in commit 628a5c561890 ("[INET]: Add IP(V6)_PMTUDISC_RPOBE").
Detalles técnicos trazas, registros y código del informe original
1. Set device MTU bigger than IP6_MAX_MTU. cork->base.fragsize will be set to that MTU in ip6_setup_cork. 2. Set IPV6_MTU_DISCOVER to IPV6_PMTUDISC_PROBE or IPV6_PMTUDISC_DO. It lets maxnonfragsize be set to device MTU (cork->fragsize) in __ip6_append_data, rather than to IP6_MAX_MTU. 3. Send 65528 bytes of payload (+8 bytes of UDP header, +40 bytes of IPv6 header). Device MTU allows it (it's only one byte bigger than IP6_MAX_MTU, and the device MTU is bigger than that). 4. The UDP length in the built packet is 65536, which overflows the 16-bit length field and triggers the WARN in udp_set_len_short.
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: 5
- 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/0ae10b6be49b425827659b23bcce498f80eb7182
- https://git.kernel.org/stable/c/1d56a00ec91f2885c64ea5b8cea18cb746b91bbb
- https://git.kernel.org/stable/c/1dd562f3019019ffdf4b396570613053facda9ee
- https://git.kernel.org/stable/c/ce66352d3eb21825410af8b91db7cc4bb8e22c98
- https://git.kernel.org/stable/c/e01b7c176d9af2b7c22bb3fe12cf9a7904f99fdc
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-97984",
"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": "427faee167bce4ccb0b22f6815a9ac509e31d4c3",
"lessThan": "1dd562f3019019ffdf4b396570613053facda9ee",
"versionType": "git"
},
{
"status": "affected",
"version": "427faee167bce4ccb0b22f6815a9ac509e31d4c3",
"lessThan": "1d56a00ec91f2885c64ea5b8cea18cb746b91bbb",
"versionType": "git"
},
{
"status": "affected",
"version": "427faee167bce4ccb0b22f6815a9ac509e31d4c3",
"lessThan": "ce66352d3eb21825410af8b91db7cc4bb8e22c98",
"versionType": "git"
},
{
"status": "affected",
"version": "427faee167bce4ccb0b22f6815a9ac509e31d4c3",
"lessThan": "e01b7c176d9af2b7c22bb3fe12cf9a7904f99fdc",
"versionType": "git"
},
{
"status": "affected",
"version": "427faee167bce4ccb0b22f6815a9ac509e31d4c3",
"lessThan": "0ae10b6be49b425827659b23bcce498f80eb7182",
"versionType": "git"
}
],
"programFiles": [
"net/ipv6/ip6_output.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.15"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.15",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.158",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.111",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.53",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.7",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3-rc3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/ipv6/ip6_output.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-09-25T11:17:26.443",
"references": [
{
"url": "https://git.kernel.org/stable/c/0ae10b6be49b425827659b23bcce498f80eb7182",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/1d56a00ec91f2885c64ea5b8cea18cb746b91bbb",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/1dd562f3019019ffdf4b396570613053facda9ee",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/ce66352d3eb21825410af8b91db7cc4bb8e22c98",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/e01b7c176d9af2b7c22bb3fe12cf9a7904f99fdc",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipv6: Fix UDP length overflow with PMTU discover and big MTU\n\nThis commit bounds cork->base.fragsize to IP6_MAX_MTU for UDP sockets to\navoid a possible overflow of UDP length that triggers a WARN in\nudp_set_len_short when setsockopt IPV6_MTU_DISCOVER is set to\nIPV6_PMTUDISC_DO or IPV6_PMTUDISC_PROBE, and a large packet is sent over\na netdev with an unusually large MTU.\n\nSteps to reproduce (included in the new selftest):\n\n1. Set device MTU bigger than IP6_MAX_MTU. cork->base.fragsize will be\n set to that MTU in ip6_setup_cork.\n2. Set IPV6_MTU_DISCOVER to IPV6_PMTUDISC_PROBE or IPV6_PMTUDISC_DO. It\n lets maxnonfragsize be set to device MTU (cork->fragsize) in\n __ip6_append_data, rather than to IP6_MAX_MTU.\n3. Send 65528 bytes of payload (+8 bytes of UDP header, +40 bytes of\n IPv6 header). Device MTU allows it (it's only one byte bigger than\n IP6_MAX_MTU, and the device MTU is bigger than that).\n4. The UDP length in the built packet is 65536, which overflows the\n 16-bit length field and triggers the WARN in udp_set_len_short.\n\nTo avoid breaking sending UDP jumbograms over raw IPv6 sockets, limit\nthe change to UDP sockets only.\n\nThe original overflow bug with IPv6 and IPV6_PMTUDISC_DO seems to\npredate git history (verified reproduction on 2.6.21), was fixed later,\nand then reappeared in commit 427faee167bc (\"net: ipv6: introduce\nip6_dst_mtu_maybe_forward\"), which is chosen as the Fixes tag here. The\noverflow with IPV6_PMTUDISC_PROBE reproduces since its introduction in\ncommit 628a5c561890 (\"[INET]: Add IP(V6)_PMTUDISC_RPOBE\")."
}
],
"lastModified": "2026-10-03T11:18:22.383",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}