{"id":"CVE-2026-98374","revision":"ee07f7ebd65a4b50bf24083c921276f3","records":[{"revision":"ee07f7ebd65a4b50bf24083c921276f3","observedAt":"2026-10-24T16:17:04.479+00:00","statement":{"source":"cve-program","id":"CVE-2026-98374","aliases":[],"title":"tcp: fix use-after-free of retransmit_skb_hint in tcp_send_synack()","description":"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.","state":0,"publishedAt":"2026-10-07T13:01:48.6+00:00","modifiedAt":"2026-10-24T14:08:34.914+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/ipv4/tcp_output.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"c31b70c9968fe9c4194d1b5d06d07596a3b680de\",\n                            \"lessThan\": \"fad6d429651e748365e93ca54645accc212f0018\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"c31b70c9968fe9c4194d1b5d06d07596a3b680de\",\n                            \"lessThan\": \"c5b4da1f403a658c1c19766be2b426003ada419f\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"c31b70c9968fe9c4194d1b5d06d07596a3b680de\",\n                            \"lessThan\": \"71d45049b0d631dfdbf3c65305f7fca676de023b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"c31b70c9968fe9c4194d1b5d06d07596a3b680de\",\n                            \"lessThan\": \"e3ea71cb1408a013ed4e8a757b815f1a919324bd\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"c31b70c9968fe9c4194d1b5d06d07596a3b680de\",\n                            \"lessThan\": \"631aa4cb45099f09e9385dd786bd291c6270bfc4\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"c31b70c9968fe9c4194d1b5d06d07596a3b680de\",\n                            \"lessThan\": \"0f87720c7e4bcab07c24888b3cf12bfe857bb90e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"c31b70c9968fe9c4194d1b5d06d07596a3b680de\",\n                            \"lessThan\": \"fe99bbeee5c5dbd3abc30721a8079ced59649d97\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/ipv4/tcp_output.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.11\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.11\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.222\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.189\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.158\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.112\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.55\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.9\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","score":8.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/fad6d429651e748365e93ca54645accc212f0018","https://git.kernel.org/stable/c/c5b4da1f403a658c1c19766be2b426003ada419f","https://git.kernel.org/stable/c/71d45049b0d631dfdbf3c65305f7fca676de023b","https://git.kernel.org/stable/c/e3ea71cb1408a013ed4e8a757b815f1a919324bd","https://git.kernel.org/stable/c/631aa4cb45099f09e9385dd786bd291c6270bfc4","https://git.kernel.org/stable/c/0f87720c7e4bcab07c24888b3cf12bfe857bb90e","https://git.kernel.org/stable/c/fe99bbeee5c5dbd3abc30721a8079ced59649d97"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98374","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-98374","identifiers":["CVE-2026-98374"]},"retained":false,"historicalAffected":[]}],"coverage":[]}