CVE-2026-74746 (GCVE-0-2026-74746)
Vulnerability from cvelistv5 – Published: 2026-08-26 14:36 – Updated: 2026-08-27 05:01
VLAI
EPSS
VEX
Title
netfilter: flowtable: publish GC-visible tuple last
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.).
Severity
9.8 (Critical)
Assigner
References
8 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
ac2a66665e231847cab11b8c8e844ce43207dd2e , < 0a00254585827f1695aa2700114af622ea754cfa
(git)
Affected: ac2a66665e231847cab11b8c8e844ce43207dd2e , < be345dcbddb4643a54252b954af974b16eda8f91 (git) Affected: ac2a66665e231847cab11b8c8e844ce43207dd2e , < 211ee5d998d92a7d548811939c65942d06c146e4 (git) Affected: ac2a66665e231847cab11b8c8e844ce43207dd2e , < d37917e7bebe078f3c17e47fd6fc1c9f6e8497b2 (git) Affected: ac2a66665e231847cab11b8c8e844ce43207dd2e , < 972fdf7c4f5c282a239c88fea614b056c33dc025 (git) Affected: ac2a66665e231847cab11b8c8e844ce43207dd2e , < d9d3050a70efe217e73a0751e55fdae6a7092620 (git) Affected: ac2a66665e231847cab11b8c8e844ce43207dd2e , < d16b71231e65cb05daea2b45701fcf09cef041e7 (git) Affected: ac2a66665e231847cab11b8c8e844ce43207dd2e , < 2014ac62df9d45bb9a004a043e85df7be09ed780 (git) |
guessed | |
| Linux | Linux |
Affected:
4.16
Unaffected: 0 , < 4.16 (semver) Unaffected: 5.10.266 , ≤ 5.10.* (semver) Unaffected: 5.15.217 , ≤ 5.15.* (semver) Unaffected: 6.1.184 , ≤ 6.1.* (semver) Unaffected: 6.6.153 , ≤ 6.6.* (semver) Unaffected: 6.12.105 , ≤ 6.12.* (semver) Unaffected: 6.18.46 , ≤ 6.18.* (semver) Unaffected: 7.1.10 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix) |
guessed |
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/netfilter/nf_flow_table_core.c"
],
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"versionType": "git"
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"vendor": "Linux",
"versions": [
{
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"version": "4.16"
},
{
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"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": [
{
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"versionEndExcluding": "5.10.266",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
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"versionEndExcluding": "5.15.217",
"versionStartIncluding": "4.16",
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},
{
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"versionEndExcluding": "6.1.184",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.105",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
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"versionEndExcluding": "6.18.46",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
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},
{
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"versionStartIncluding": "4.16",
"vulnerable": true
}
],
"negate": false,
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}
]
}
],
"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": {
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}
}
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"cveMetadata": {
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"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",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-74746",
"date": "2026-08-27",
"epss": "0.00543",
"percentile": "0.43345"
},
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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.).\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/netfilter/nf_flow_table_core.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"ac2a66665e231847cab11b8c8e844ce43207dd2e\",\"lessThan\":\"0a00254585827f1695aa2700114af622ea754cfa\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ac2a66665e231847cab11b8c8e844ce43207dd2e\",\"lessThan\":\"be345dcbddb4643a54252b954af974b16eda8f91\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ac2a66665e231847cab11b8c8e844ce43207dd2e\",\"lessThan\":\"211ee5d998d92a7d548811939c65942d06c146e4\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ac2a66665e231847cab11b8c8e844ce43207dd2e\",\"lessThan\":\"d37917e7bebe078f3c17e47fd6fc1c9f6e8497b2\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ac2a66665e231847cab11b8c8e844ce43207dd2e\",\"lessThan\":\"972fdf7c4f5c282a239c88fea614b056c33dc025\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ac2a66665e231847cab11b8c8e844ce43207dd2e\",\"lessThan\":\"d9d3050a70efe217e73a0751e55fdae6a7092620\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ac2a66665e231847cab11b8c8e844ce43207dd2e\",\"lessThan\":\"d16b71231e65cb05daea2b45701fcf09cef041e7\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ac2a66665e231847cab11b8c8e844ce43207dd2e\",\"lessThan\":\"2014ac62df9d45bb9a004a043e85df7be09ed780\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/netfilter/nf_flow_table_core.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"4.16\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"4.16\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.10.266\",\"lessThanOrEqual\":\"5.10.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.217\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.184\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.153\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.105\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.46\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.10\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":9.8,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0a00254585827f1695aa2700114af622ea754cfa\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/2014ac62df9d45bb9a004a043e85df7be09ed780\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/211ee5d998d92a7d548811939c65942d06c146e4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/972fdf7c4f5c282a239c88fea614b056c33dc025\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/be345dcbddb4643a54252b954af974b16eda8f91\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d16b71231e65cb05daea2b45701fcf09cef041e7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d37917e7bebe078f3c17e47fd6fc1c9f6e8497b2\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d9d3050a70efe217e73a0751e55fdae6a7092620\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
"redhat_vex": {
"aggregate_severity": "Important",
"current_release_date": "2026-08-27T12:10:34+00:00",
"cve": "CVE-2026-74746",
"id": "CVE-2026-74746",
"initial_release_date": "2026-08-26T00:00:00+00:00",
"product_status:known_affected": "232",
"product_status:known_not_affected": "42",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: netfilter: flowtable: publish GC-visible tuple last",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74746.json",
"version": "3"
}
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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