CVE-2026-80664 (GCVE-0-2026-80664)
Vulnerability from cvelistv5
Published
2026-08-28 06:49
Modified
2026-08-29 06:21
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
netfilter: xt_nat: reject unsupported target families
xt_nat SNAT and DNAT target handlers assume IP-family conntrack state
is present and can dereference a NULL pointer when instantiated from an
unsupported family through nft_compat. A bridge-family compat rule can
therefore trigger a NULL-dereference in nf_nat_setup_info().
Reject non-IP families in xt_nat_checkentry() so unsupported targets
cannot be installed. Keep NFPROTO_INET allowed for valid inet NAT
compat users and leave the runtime fast path unchanged.
[ The crash was fixed via
9dbba7e694ec ("netfilter: nft_compat: ebtables emulation must reject non-bridge targets"),
so this patch is no longer critical.
Nevertheless, NAT is only relevant for ipv4/ipv6, so this extra
family check is a good idea in any case. ]
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: c7232c9979cba684c50b64c513c4a83c9aa70563 Version: c7232c9979cba684c50b64c513c4a83c9aa70563 Version: c7232c9979cba684c50b64c513c4a83c9aa70563 Version: c7232c9979cba684c50b64c513c4a83c9aa70563 Version: c7232c9979cba684c50b64c513c4a83c9aa70563 Version: c7232c9979cba684c50b64c513c4a83c9aa70563 Version: c7232c9979cba684c50b64c513c4a83c9aa70563 Version: c7232c9979cba684c50b64c513c4a83c9aa70563 |
||
{
"containers": {
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"product": "Linux",
"programFiles": [
"net/netfilter/xt_nat.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"vendor": "Linux",
"versions": [
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"version": "3.7"
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"status": "unaffected",
"version": "0",
"versionType": "semver"
},
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"status": "unaffected",
"version": "5.10.261",
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},
{
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"status": "unaffected",
"version": "5.15.212",
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},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
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},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
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{
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"status": "unaffected",
"version": "6.12.97",
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},
{
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"status": "unaffected",
"version": "6.18.40",
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{
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"status": "unaffected",
"version": "7.1.5",
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{
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"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
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"nodes": [
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: xt_nat: reject unsupported target families\n\nxt_nat SNAT and DNAT target handlers assume IP-family conntrack state\nis present and can dereference a NULL pointer when instantiated from an\nunsupported family through nft_compat. A bridge-family compat rule can\ntherefore trigger a NULL-dereference in nf_nat_setup_info().\n\nReject non-IP families in xt_nat_checkentry() so unsupported targets\ncannot be installed. Keep NFPROTO_INET allowed for valid inet NAT\ncompat users and leave the runtime fast path unchanged.\n\n[ The crash was fixed via\n 9dbba7e694ec (\"netfilter: nft_compat: ebtables emulation must reject non-bridge targets\"),\n so this patch is no longer critical.\n Nevertheless, NAT is only relevant for ipv4/ipv6, so this extra\n family check is a good idea in any case. ]"
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.3,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - Exploitation requires installing a bridge-family nft_compat SNAT/DNAT rule via NETLINK_NETFILTER (nftables netlink), a local syscall path; although matching bridge traffic can trigger evaluation, the vulnerable rule state cannot be created without local netfilter administration.\nAC:L - Once CAP_NET_ADMIN is held in the target network namespace, xt_request_find_target() deterministically resolves UNSPEC-family SNAT/DNAT rev 1/2 targets for bridge chains, and sending bridge traffic through the committed rule reliably reaches nf_nat_setup_info() with a NULL nf_conn from nf_ct_get().\nPR:L - All nfnetlink handlers are gated by netlink_net_capable(skb, CAP_NET_ADMIN), which checks capability in the socket network namespace user namespace; unprivileged local users routinely obtain CAP_NET_ADMIN via user and network namespaces (unshare -Urn), enabling installation of the malicious bridge compat rule.\nUI:N - No victim interaction is required beyond the attacker obtaining namespace-local CAP_NET_ADMIN, creating a bridge nftables chain with a compat SNAT/DNAT target, and delivering matching bridge traffic; no third-party actions such as mounting filesystems or opening files are needed.\nS:U - Impact is confined to the host kernel netfilter/NAT subsystem within the same security authority; this is not a VM escape, hypervisor boundary crossing, or IOMMU/DMA sandbox bypass, but standard in-kernel misbehavior from an invalid family/target pairing.\nC:L - The primary runtime failure is a NULL nf_conn dereference in nf_nat_setup_info(), and the surrounding nft_compat bridge/xtables semantic mismatch can leak limited kernel information via oops register dumps and crash logs readable by the local attacker who triggered the fault.\nI:H - Missing family validation lets IP-family NAT targets execute under bridge nft_compat semantics where nf_ct_get() yields NULL, constituting a type/family confusion that can corrupt netfilter verdict and NAT handling before faulting; mis-instantiated SNAT/DNAT targets should not run in bridge context at all.\nA:H - Passing bridge traffic through a bridge-family compat SNAT/DNAT rule causes nf_nat_setup_info() to dereference the NULL connection from nf_ct_get(), producing a kernel oops or panic; repeated matching traffic can retrigger the crash for sustained denial of service."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-29T06:21:50.580Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/49abe564391411057a26a9a943c8e17867c3b9b4"
},
{
"url": "https://git.kernel.org/stable/c/0afc9ad987c0faa80ab5f8d6e7815085ac8dbb82"
},
{
"url": "https://git.kernel.org/stable/c/4fbc2bac02edabb665beb2aa87ca6f1e1d4c4777"
},
{
"url": "https://git.kernel.org/stable/c/a842dab87cab29f2a5798a47b2dc5e6a449950bf"
},
{
"url": "https://git.kernel.org/stable/c/e35c048d7511e9d4c2a537b8a231c49606e97c16"
},
{
"url": "https://git.kernel.org/stable/c/679ced28a9dc2f6dc679eb05027d779693e60902"
},
{
"url": "https://git.kernel.org/stable/c/ec88fa71c82072e9189983b05b499d3507550271"
},
{
"url": "https://git.kernel.org/stable/c/5d1a2240935ea47e2673d0ea17fdb058e4dc91dd"
}
],
"title": "netfilter: xt_nat: reject unsupported target families",
"x_generator": {
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}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-80664",
"datePublished": "2026-08-28T06:49:07.478Z",
"dateReserved": "2026-08-26T14:34:25.781Z",
"dateUpdated": "2026-08-29T06:21:50.580Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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