CVE-2026-43026 (GCVE-0-2026-43026)
Vulnerability from cvelistv5
Published
2026-05-01 14:15
Modified
2026-05-01 14:15
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ctnetlink: zero expect NAT fields when CTA_EXPECT_NAT absent
ctnetlink_alloc_expect() allocates expectations from a non-zeroing
slab cache via nf_ct_expect_alloc(). When CTA_EXPECT_NAT is not
present in the netlink message, saved_addr and saved_proto are
never initialized. Stale data from a previous slab occupant can
then be dumped to userspace by ctnetlink_exp_dump_expect(), which
checks these fields to decide whether to emit CTA_EXPECT_NAT.
The safe sibling nf_ct_expect_init(), used by the packet path,
explicitly zeroes these fields.
Zero saved_addr, saved_proto and dir in the else branch, guarded
by IS_ENABLED(CONFIG_NF_NAT) since these fields only exist when
NAT is enabled.
Confirmed by priming the expect slab with NAT-bearing expectations,
freeing them, creating a new expectation without CTA_EXPECT_NAT,
and observing that the ctnetlink dump emits a spurious
CTA_EXPECT_NAT containing stale data from the prior allocation.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 076a0ca02644657b13e4af363f487ced2942e9cb Version: 076a0ca02644657b13e4af363f487ced2942e9cb Version: 076a0ca02644657b13e4af363f487ced2942e9cb Version: 076a0ca02644657b13e4af363f487ced2942e9cb Version: 076a0ca02644657b13e4af363f487ced2942e9cb Version: 076a0ca02644657b13e4af363f487ced2942e9cb Version: 076a0ca02644657b13e4af363f487ced2942e9cb Version: 076a0ca02644657b13e4af363f487ced2942e9cb |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/netfilter/nf_conntrack_netlink.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "a5a89db6981a1ddf2314bf50cb49db5a3146185f",
"status": "affected",
"version": "076a0ca02644657b13e4af363f487ced2942e9cb",
"versionType": "git"
},
{
"lessThan": "1c2ebdeff8d088a2e47ae25d7b38447249adace2",
"status": "affected",
"version": "076a0ca02644657b13e4af363f487ced2942e9cb",
"versionType": "git"
},
{
"lessThan": "a64b7bf84b4d5ea54218c5d374ec87fff9000f43",
"status": "affected",
"version": "076a0ca02644657b13e4af363f487ced2942e9cb",
"versionType": "git"
},
{
"lessThan": "2898080c054ea4d6ddfaaf21bbedbc229a9a8376",
"status": "affected",
"version": "076a0ca02644657b13e4af363f487ced2942e9cb",
"versionType": "git"
},
{
"lessThan": "fd002ff2ea030cbfb0188a11b3c60ce7f84485f4",
"status": "affected",
"version": "076a0ca02644657b13e4af363f487ced2942e9cb",
"versionType": "git"
},
{
"lessThan": "929f7a9a7aad9404a5867216c3f8738232355b38",
"status": "affected",
"version": "076a0ca02644657b13e4af363f487ced2942e9cb",
"versionType": "git"
},
{
"lessThan": "bff0f4f06f12d6d9bc565a3e1378abd4f6f5ce36",
"status": "affected",
"version": "076a0ca02644657b13e4af363f487ced2942e9cb",
"versionType": "git"
},
{
"lessThan": "35177c6877134a21315f37d57a5577846225623e",
"status": "affected",
"version": "076a0ca02644657b13e4af363f487ced2942e9cb",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/netfilter/nf_conntrack_netlink.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "3.4"
},
{
"lessThan": "3.4",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.253",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.203",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.168",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.134",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.81",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.22",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.12",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.10.253",
"versionStartIncluding": "3.4",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.203",
"versionStartIncluding": "3.4",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.168",
"versionStartIncluding": "3.4",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.134",
"versionStartIncluding": "3.4",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.81",
"versionStartIncluding": "3.4",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.22",
"versionStartIncluding": "3.4",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.19.12",
"versionStartIncluding": "3.4",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.0",
"versionStartIncluding": "3.4",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ctnetlink: zero expect NAT fields when CTA_EXPECT_NAT absent\n\nctnetlink_alloc_expect() allocates expectations from a non-zeroing\nslab cache via nf_ct_expect_alloc(). When CTA_EXPECT_NAT is not\npresent in the netlink message, saved_addr and saved_proto are\nnever initialized. Stale data from a previous slab occupant can\nthen be dumped to userspace by ctnetlink_exp_dump_expect(), which\nchecks these fields to decide whether to emit CTA_EXPECT_NAT.\n\nThe safe sibling nf_ct_expect_init(), used by the packet path,\nexplicitly zeroes these fields.\n\nZero saved_addr, saved_proto and dir in the else branch, guarded\nby IS_ENABLED(CONFIG_NF_NAT) since these fields only exist when\nNAT is enabled.\n\nConfirmed by priming the expect slab with NAT-bearing expectations,\nfreeing them, creating a new expectation without CTA_EXPECT_NAT,\nand observing that the ctnetlink dump emits a spurious\nCTA_EXPECT_NAT containing stale data from the prior allocation."
}
],
"providerMetadata": {
"dateUpdated": "2026-05-01T14:15:27.854Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/a5a89db6981a1ddf2314bf50cb49db5a3146185f"
},
{
"url": "https://git.kernel.org/stable/c/1c2ebdeff8d088a2e47ae25d7b38447249adace2"
},
{
"url": "https://git.kernel.org/stable/c/a64b7bf84b4d5ea54218c5d374ec87fff9000f43"
},
{
"url": "https://git.kernel.org/stable/c/2898080c054ea4d6ddfaaf21bbedbc229a9a8376"
},
{
"url": "https://git.kernel.org/stable/c/fd002ff2ea030cbfb0188a11b3c60ce7f84485f4"
},
{
"url": "https://git.kernel.org/stable/c/929f7a9a7aad9404a5867216c3f8738232355b38"
},
{
"url": "https://git.kernel.org/stable/c/bff0f4f06f12d6d9bc565a3e1378abd4f6f5ce36"
},
{
"url": "https://git.kernel.org/stable/c/35177c6877134a21315f37d57a5577846225623e"
}
],
"title": "netfilter: ctnetlink: zero expect NAT fields when CTA_EXPECT_NAT absent",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-43026",
"datePublished": "2026-05-01T14:15:27.854Z",
"dateReserved": "2026-05-01T14:12:55.976Z",
"dateUpdated": "2026-05-01T14:15:27.854Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
Loading…
Loading…
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.
Loading…
Loading…