{"id":"CVE-2026-68136","revision":"923535b5507348b29b9e07426a0b6095","records":[{"revision":"923535b5507348b29b9e07426a0b6095","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-68136","aliases":[],"title":"net: gro: fix double aggregation of flush-marked skbs","description":"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().","state":0,"publishedAt":"2026-08-10T11:58:59.45+00:00","modifiedAt":"2026-10-19T20:58:52.839+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/core/gro.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"3a1296a38d0cf62bffb9a03c585cbd5dbf15d596\",\n                            \"lessThan\": \"7fc7e35212cf58c134310fb47566a844297ceae9\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3a1296a38d0cf62bffb9a03c585cbd5dbf15d596\",\n                            \"lessThan\": \"d1fb23f8f794ac4683127bd49a6422bd87e0ac02\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3a1296a38d0cf62bffb9a03c585cbd5dbf15d596\",\n                            \"lessThan\": \"db3e82da616f52e2b27e25e7be3fde2f2a5e54d6\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3a1296a38d0cf62bffb9a03c585cbd5dbf15d596\",\n                            \"lessThan\": \"107e1a469f53a2a70874f3f12bf6fcd23925da1d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3a1296a38d0cf62bffb9a03c585cbd5dbf15d596\",\n                            \"lessThan\": \"a4dfd46cc8f08a29c6183794790547d0945f3d45\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3a1296a38d0cf62bffb9a03c585cbd5dbf15d596\",\n                            \"lessThan\": \"fc0c0f7a207f0cd2d2aa725696c907f7d03af9e0\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3a1296a38d0cf62bffb9a03c585cbd5dbf15d596\",\n                            \"lessThan\": \"e751256486d0ded20f5a9f9863467f1dce65142f\",\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/core/gro.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.6\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.6\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.266\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.184\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.153\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.101\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.42\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1.6\",\n                            \"lessThanOrEqual\": \"7.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2\",\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:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/7fc7e35212cf58c134310fb47566a844297ceae9","https://git.kernel.org/stable/c/d1fb23f8f794ac4683127bd49a6422bd87e0ac02","https://git.kernel.org/stable/c/db3e82da616f52e2b27e25e7be3fde2f2a5e54d6","https://git.kernel.org/stable/c/107e1a469f53a2a70874f3f12bf6fcd23925da1d","https://git.kernel.org/stable/c/a4dfd46cc8f08a29c6183794790547d0945f3d45","https://git.kernel.org/stable/c/fc0c0f7a207f0cd2d2aa725696c907f7d03af9e0","https://git.kernel.org/stable/c/e751256486d0ded20f5a9f9863467f1dce65142f"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-68136","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-68136","identifiers":["CVE-2026-68136"]},"retained":false,"historicalAffected":[]}],"coverage":[]}