CVE-2026-74746 (GCVE-0-2026-74746)
Vulnerability from cvelistv5
Published
2026-08-26 14:36
Modified
2026-08-27 05:01
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
netfilter: flowtable: publish GC-visible tuple last
nf_flow_table_iterate() only treats original-direction tuple nodes as
owning entries. Publishing the original node first lets GC observe and
free a flow while flow_offload_add() is still inserting the reply node.
Publish the reply node first and the original node last so GC never
sees a partially installed flow.
KASAN can trigger slab-use-after-free read and write reports in the
flowtable/rhashtable path (rht_deferred_worker, jhash, flow_offload_del,
flow_offload_lookup, etc.).
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: ac2a66665e231847cab11b8c8e844ce43207dd2e Version: ac2a66665e231847cab11b8c8e844ce43207dd2e Version: ac2a66665e231847cab11b8c8e844ce43207dd2e Version: ac2a66665e231847cab11b8c8e844ce43207dd2e Version: ac2a66665e231847cab11b8c8e844ce43207dd2e Version: ac2a66665e231847cab11b8c8e844ce43207dd2e Version: ac2a66665e231847cab11b8c8e844ce43207dd2e Version: ac2a66665e231847cab11b8c8e844ce43207dd2e |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/netfilter/nf_flow_table_core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "0a00254585827f1695aa2700114af622ea754cfa",
"status": "affected",
"version": "ac2a66665e231847cab11b8c8e844ce43207dd2e",
"versionType": "git"
},
{
"lessThan": "be345dcbddb4643a54252b954af974b16eda8f91",
"status": "affected",
"version": "ac2a66665e231847cab11b8c8e844ce43207dd2e",
"versionType": "git"
},
{
"lessThan": "211ee5d998d92a7d548811939c65942d06c146e4",
"status": "affected",
"version": "ac2a66665e231847cab11b8c8e844ce43207dd2e",
"versionType": "git"
},
{
"lessThan": "d37917e7bebe078f3c17e47fd6fc1c9f6e8497b2",
"status": "affected",
"version": "ac2a66665e231847cab11b8c8e844ce43207dd2e",
"versionType": "git"
},
{
"lessThan": "972fdf7c4f5c282a239c88fea614b056c33dc025",
"status": "affected",
"version": "ac2a66665e231847cab11b8c8e844ce43207dd2e",
"versionType": "git"
},
{
"lessThan": "d9d3050a70efe217e73a0751e55fdae6a7092620",
"status": "affected",
"version": "ac2a66665e231847cab11b8c8e844ce43207dd2e",
"versionType": "git"
},
{
"lessThan": "d16b71231e65cb05daea2b45701fcf09cef041e7",
"status": "affected",
"version": "ac2a66665e231847cab11b8c8e844ce43207dd2e",
"versionType": "git"
},
{
"lessThan": "2014ac62df9d45bb9a004a043e85df7be09ed780",
"status": "affected",
"version": "ac2a66665e231847cab11b8c8e844ce43207dd2e",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/netfilter/nf_flow_table_core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.16"
},
{
"lessThan": "4.16",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.266",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.217",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.184",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.153",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.105",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.46",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.10",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.10.266",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.217",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.184",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.153",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.105",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.46",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.10",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "4.16",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: flowtable: publish GC-visible tuple last\n\nnf_flow_table_iterate() only treats original-direction tuple nodes as\nowning entries. Publishing the original node first lets GC observe and\nfree a flow while flow_offload_add() is still inserting the reply node.\nPublish the reply node first and the original node last so GC never\nsees a partially installed flow.\n\nKASAN can trigger slab-use-after-free read and write reports in the\nflowtable/rhashtable path (rht_deferred_worker, jhash, flow_offload_del,\nflow_offload_lookup, etc.)."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - flow_offload_add runs from nft_flow_offload_eval on the FORWARD hook and from tc act_ct during softirq packet processing when remote TCP/UDP traffic creates new offloaded conntrack flows on nftables flowtable routers/gateways, not through netlink configuration APIs.\nAC:L - The attacker controls when flows are offloaded (packet rate/timing) and can race connection teardown so nf_flow_table_gc_run observes a partially installed original tuple while reply insertion is still in progress; both the insert and GC sides of the race are attacker-driven.\nPR:N - On the intended edge-router/OpenWrt deployment, nftables flow offload is an administrator prerequisite; a remote sender needs no local account, authentication, or CAP_NET_ADMIN on the victim to trigger flow_offload_add while forwarding traffic.\nUI:N - Exploitation requires only sending network packets processed automatically on the forwarding or ingress path; no victim must open files, mount filesystems, or take any interactive action beyond normal traffic through the router.\nS:U - Slab use-after-free in the flowtable rhashtable/GC path affects only in-kernel memory on the affected host; this is standard kernel compromise within one security authority, not a VM escape, IOMMU bypass, or cross-boundary sandbox break.\nC:H - The fix commit documents KASAN slab-use-after-free read and write reports in rht_deferred_worker, jhash, flow_offload_del, and flow_offload_lookup; UAF on flow_offload kmem-cache objects enables arbitrary kernel memory disclosure via heap grooming.\nI:H - Freed flow_offload structures remain reachable during concurrent rhashtable insert/remove and deferred worker operations, providing attacker-influenceable heap corruption that can be groomed into arbitrary kernel writes and control-flow hijack.\nA:H - Concurrent GC freeing of a partially inserted flow while flow_offload_add or rhashtable workers still access it causes kernel oops/panic and reliable denial of service; UAF on the flow offload path can crash forwarding routers under sustained malicious traffic."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-27T05:01:07.405Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/0a00254585827f1695aa2700114af622ea754cfa"
},
{
"url": "https://git.kernel.org/stable/c/be345dcbddb4643a54252b954af974b16eda8f91"
},
{
"url": "https://git.kernel.org/stable/c/211ee5d998d92a7d548811939c65942d06c146e4"
},
{
"url": "https://git.kernel.org/stable/c/d37917e7bebe078f3c17e47fd6fc1c9f6e8497b2"
},
{
"url": "https://git.kernel.org/stable/c/972fdf7c4f5c282a239c88fea614b056c33dc025"
},
{
"url": "https://git.kernel.org/stable/c/d9d3050a70efe217e73a0751e55fdae6a7092620"
},
{
"url": "https://git.kernel.org/stable/c/d16b71231e65cb05daea2b45701fcf09cef041e7"
},
{
"url": "https://git.kernel.org/stable/c/2014ac62df9d45bb9a004a043e85df7be09ed780"
}
],
"title": "netfilter: flowtable: publish GC-visible tuple last",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74746",
"datePublished": "2026-08-26T14:36:55.963Z",
"dateReserved": "2026-08-15T05:44:03.931Z",
"dateUpdated": "2026-08-27T05:01:07.405Z",
"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…