{"schema":"threatline.record/2","record":{"id":"CVE-2026-68136","aliases":[],"summary":"net: gro: fix double aggregation of flush-marked skbs","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: gro: fix double aggregation of flush-marked skbs\n\nCommit 0ab03f353d36 (\"net-gro: Fix GRO flush when receiving a GSO\npacket.\") added a flush check to skb_gro_receive(), but\nskb_gro_receive_list() lacks the same validation.\n\nAs a result, packets marked with NAPI_GRO_CB(skb)->flush may still be\nre-aggregated.\n\nThis allows already-GRO'd packets with existing frag_list to be\nre-aggregated into a new GRO session, corrupting the frag_list chain\nstructure. When skb_segment() attempts to unpack these malformed packets,\nit encounters invalid state and triggers a kernel panic.\n\nScenario (Tethering/Device forwarding):\n  1. Driver: Generated aggregated packet P1 via LRO with frag_list\n  2. Dev A: Receives aggregated fraglist packet and flush flag set\n  3. Dev A: Re-enters GRO, skb_gro_receive_list() is called\n  4. Missing flush check allows re-aggregation despite flush flag\n  5. Frag_list chain becomes corrupted (loops or dangling refs)\n  6. Dev B: TX path calls skb_segment(), crashes on corrupted frag_list\n\nRoot cause in skb_segment():\n  The check at line ~4891:\n    if (hsize <= 0 && i >= nfrags && skb_headlen(list_skb) &&\n        (skb_headlen(list_skb) == len || sg)) {\n\n  When frag_list is corrupted by double aggregation, when list_skb is\n  a NULL pointer from skb->next, skb_headlen(list_skb) dereference\n  NULL/corrupted pointers occurs.\n\nCall Trace:\n skb_headlen(NULL skb)\n skb_segment\n tcp_gso_segment\n tcp4_gso_segment\n inet_gso_segment\n skb_mac_gso_segment\n __skb_gso_segment\n skb_gso_segment\n validate_xmit_skb\n validate_xmit_skb_list\n sch_direct_xmit\n qdisc_restart\n __qdisc_run\n qdisc_run\n net_tx_action\n\nFix: Add NAPI_GRO_CB(skb)->flush validation to the early-return check in\nskb_gro_receive_list(), matching the defensive programming pattern of\nskb_gro_receive().","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-68136","source_modified_at":"2026-10-19T20:58:52.839Z","fetched_at":"2026-10-24T00:31:04.721601Z","product":"Linux","vendor":"Linux","versions":[{"version":"3a1296a38d0cf62bffb9a03c585cbd5dbf15d596","lessThan":"7fc7e35212cf58c134310fb47566a844297ceae9","status":"affected","versionType":"git"},{"version":"3a1296a38d0cf62bffb9a03c585cbd5dbf15d596","lessThan":"d1fb23f8f794ac4683127bd49a6422bd87e0ac02","status":"affected","versionType":"git"},{"version":"3a1296a38d0cf62bffb9a03c585cbd5dbf15d596","lessThan":"db3e82da616f52e2b27e25e7be3fde2f2a5e54d6","status":"affected","versionType":"git"},{"version":"3a1296a38d0cf62bffb9a03c585cbd5dbf15d596","lessThan":"107e1a469f53a2a70874f3f12bf6fcd23925da1d","status":"affected","versionType":"git"},{"version":"3a1296a38d0cf62bffb9a03c585cbd5dbf15d596","lessThan":"a4dfd46cc8f08a29c6183794790547d0945f3d45","status":"affected","versionType":"git"},{"version":"3a1296a38d0cf62bffb9a03c585cbd5dbf15d596","lessThan":"fc0c0f7a207f0cd2d2aa725696c907f7d03af9e0","status":"affected","versionType":"git"},{"version":"3a1296a38d0cf62bffb9a03c585cbd5dbf15d596","lessThan":"e751256486d0ded20f5a9f9863467f1dce65142f","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-68136","source_modified_at":"2026-10-19T20:58:52.839Z","fetched_at":"2026-10-24T00:31:04.721601Z","product":"Linux","vendor":"Linux","versions":[{"version":"5.6","status":"affected"},{"version":"0","lessThan":"5.6","status":"unaffected","versionType":"semver"},{"version":"5.10.266","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"6.1.184","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.153","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.101","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.42","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.6","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-68136","source_modified_at":"2026-10-19T20:58:52.839Z","fetched_at":"2026-10-24T00:31:04.721601Z","package":{"name":"Linux","ecosystem":null},"version":"7fc7e35212cf58c134310fb47566a844297ceae9","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-68136","source_modified_at":"2026-10-19T20:58:52.839Z","fetched_at":"2026-10-24T00:31:04.721601Z","package":{"name":"Linux","ecosystem":null},"version":"107e1a469f53a2a70874f3f12bf6fcd23925da1d","basis":"first unaffected version stated in the CVE record"}],"cvss":9.8,"severity":"Critical","kev":{"listed":false},"epss":{"probability":0.00539,"percentile":0.44598,"score_date":"2026-10-23"},"published_at":"2026-08-10T11:58:59.450Z","modified_at":"2026-10-19T20:58:52.839Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-68136","fetched_at":"2026-10-24T00:31:04.721601Z","source_modified_at":"2026-10-19T20:58:52.839Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-68136","fetched_at":"2026-10-24T00:31:04.721601Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/7fc7e35212cf58c134310fb47566a844297ceae9"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/d1fb23f8f794ac4683127bd49a6422bd87e0ac02"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/db3e82da616f52e2b27e25e7be3fde2f2a5e54d6"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/107e1a469f53a2a70874f3f12bf6fcd23925da1d"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/a4dfd46cc8f08a29c6183794790547d0945f3d45"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/fc0c0f7a207f0cd2d2aa725696c907f7d03af9e0"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/e751256486d0ded20f5a9f9863467f1dce65142f"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","ssvc":{"exploitation":"none","automatable":"yes","technical_impact":"total","assessed_at":"2026-10-16T15:44:29.127961Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T20:58:52.839Z","content_hash":"111ced97b19314274e8a6e60d09a0acdab0522c870b8c1faf439ceb49c65dd33"}}