CVE-2026-72256
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_cluster: reject template conntracks in hash match xt_cluster_mt() treats any non-NULL nf_ct_get() result as a fully initialized conntrack and passes it to xt_cluster_hash(). This causes a state confusion bug when the raw table CT target attaches a template conntrack to skb->_nfct before normal conntrack processing. Templates carry IPS_TEMPLATE status but do not have a valid tuple for hashing yet, so xt_cluster_hash() can hit its WARN_ON() path on the zeroed l3num field. Reject template conntracks before hashing them. This matches existing netfilter handling for template objects and avoids hashing incomplete conntrack state.
Severity
Not scored
CVSS score
Not available
Vulnerability status
Received
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-08-15 06:21:53.310000
Last modified
2026-11-06 17:19:41.467000
View original CVE JSON
{
"id": "CVE-2026-72256",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-08-15T06:21:53.310",
"lastModified": "2026-11-06T17:19:41.467",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: xt_cluster: reject template conntracks in hash match\n\nxt_cluster_mt() treats any non-NULL nf_ct_get() result as a fully\ninitialized conntrack and passes it to xt_cluster_hash().\n\nThis causes a state confusion bug when the raw table CT target attaches\na template conntrack to skb->_nfct before normal conntrack processing.\nTemplates carry IPS_TEMPLATE status but do not have a valid tuple for\nhashing yet, so xt_cluster_hash() can hit its WARN_ON() path on the\nzeroed l3num field.\n\nReject template conntracks before hashing them. This matches existing\nnetfilter handling for template objects and avoids hashing incomplete\nconntrack state."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"net/netfilter/xt_cluster.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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{
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"versionType": "git",
"status": "affected"
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{
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"programFiles": [
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"status": "unaffected"
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{
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"status": "unaffected"
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{
"version": "5.15.212",
"lessThanOrEqual": "5.15.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.1.178",
"lessThanOrEqual": "6.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.6.145",
"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.97",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.40",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.1.5",
"lessThanOrEqual": "7.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-11-06T16:53:38.810465Z",
"id": "CVE-2026-72256",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
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{
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"role": "CISA Coordinator",
"version": "2.0.3"
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}