{"schema":"threatline.record/2","record":{"id":"CVE-2026-98374","aliases":[],"summary":"tcp: fix use-after-free of retransmit_skb_hint in tcp_send_synack()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: fix use-after-free of retransmit_skb_hint in tcp_send_synack()\n\nWhen tcp_send_synack() replaces the cloned SYN skb at the head of the\nretransmit queue with a copy, it frees the original with\ntcp_rtx_queue_unlink_and_free() and only repairs tp->highest_sack.\ntp->retransmit_skb_hint keeps pointing at the freed\nskbuff_fclone_cache object.\n\nThe dangling hint is read in tcp_verify_retransmit_hint() and used as\nthe root of the rbtree walk in tcp_xmit_retransmit_queue().  An\nunprivileged TFO client (sendmsg(MSG_FASTOPEN)) can arm the hint with\nan attacker-supplied ICMP fragmentation-needed message, after which a\nsimultaneous open frees the armed SYN skb:\n\n  BUG: KASAN: slab-use-after-free in tcp_mark_skb_lost (net/ipv4/tcp_input.c:1316)\n  Read of size 4 at addr ffff88800604d928 by task swapper/1/0\n  Call Trace:\n   tcp_mark_skb_lost (net/ipv4/tcp_input.c:1316)\n   tcp_simple_retransmit (net/ipv4/tcp_input.c:3158)\n   tcp_v4_err (net/ipv4/tcp_ipv4.c:587)\n\nSync the hint to the copy.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98374","source_modified_at":"2026-10-19T09:18:26.132Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"c31b70c9968fe9c4194d1b5d06d07596a3b680de","lessThan":"fad6d429651e748365e93ca54645accc212f0018","status":"affected","versionType":"git"},{"version":"c31b70c9968fe9c4194d1b5d06d07596a3b680de","lessThan":"c5b4da1f403a658c1c19766be2b426003ada419f","status":"affected","versionType":"git"},{"version":"c31b70c9968fe9c4194d1b5d06d07596a3b680de","lessThan":"71d45049b0d631dfdbf3c65305f7fca676de023b","status":"affected","versionType":"git"},{"version":"c31b70c9968fe9c4194d1b5d06d07596a3b680de","lessThan":"e3ea71cb1408a013ed4e8a757b815f1a919324bd","status":"affected","versionType":"git"},{"version":"c31b70c9968fe9c4194d1b5d06d07596a3b680de","lessThan":"631aa4cb45099f09e9385dd786bd291c6270bfc4","status":"affected","versionType":"git"},{"version":"c31b70c9968fe9c4194d1b5d06d07596a3b680de","lessThan":"0f87720c7e4bcab07c24888b3cf12bfe857bb90e","status":"affected","versionType":"git"},{"version":"c31b70c9968fe9c4194d1b5d06d07596a3b680de","lessThan":"fe99bbeee5c5dbd3abc30721a8079ced59649d97","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98374","source_modified_at":"2026-10-19T09:18:26.132Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"5.11","status":"affected"},{"version":"0","lessThan":"5.11","status":"unaffected","versionType":"semver"},{"version":"5.15.222","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.189","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.112","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.55","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.9","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98374","source_modified_at":"2026-10-19T09:18:26.132Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"71d45049b0d631dfdbf3c65305f7fca676de023b","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98374","source_modified_at":"2026-10-19T09:18:26.132Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"631aa4cb45099f09e9385dd786bd291c6270bfc4","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98374","source_modified_at":"2026-10-19T09:18:26.132Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"0f87720c7e4bcab07c24888b3cf12bfe857bb90e","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00161,"percentile":0.04914,"score_date":"2026-10-23"},"published_at":"2026-10-07T13:01:48.600Z","modified_at":"2026-10-19T09:18:26.132Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98374","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-19T09:18:26.132Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98374","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/fad6d429651e748365e93ca54645accc212f0018"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/c5b4da1f403a658c1c19766be2b426003ada419f"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/71d45049b0d631dfdbf3c65305f7fca676de023b"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/e3ea71cb1408a013ed4e8a757b815f1a919324bd"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/631aa4cb45099f09e9385dd786bd291c6270bfc4"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/0f87720c7e4bcab07c24888b3cf12bfe857bb90e"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/fe99bbeee5c5dbd3abc30721a8079ced59649d97"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T09:18:26.132Z","content_hash":"20762ee972d37a6a0dd057affcc6997468437de07fdaaa82dc897c38748a000a"}}