{"api_version":"1","generated_at":"2026-08-28T17:32:22+00:00","cve":"CVE-2026-74746","urls":{"html":"https://cve.report/CVE-2026-74746","api":"https://cve.report/api/cve/CVE-2026-74746.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74746","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74746"},"summary":{"title":"netfilter: flowtable: publish GC-visible tuple last","description":"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.).","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-26 15:16:53","updated_at":"2026-08-27 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original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"74746","cve":"CVE-2026-74746","epss":"0.005430000","percentile":"0.433450000","score_date":"2026-08-27","updated_at":"2026-08-28 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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"},"nvd":{"publishedDate":"2026-08-26 15:16:53","lastModifiedDate":"2026-08-27 06:17:25","problem_types":[],"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}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74746","Ordinal":"1","Title":"netfilter: flowtable: publish GC-visible tuple last","CVE":"CVE-2026-74746","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74746","Ordinal":"1","NoteData":"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.).","Type":"Description","Title":"netfilter: flowtable: publish GC-visible tuple last"}]}}}