{"id":"CVE-2026-99282","revision":"6346397e91a1446193c34c278ba5f2a4","records":[{"revision":"6346397e91a1446193c34c278ba5f2a4","observedAt":"2026-11-07T16:07:43.282+00:00","statement":{"source":"cve-program","id":"CVE-2026-99282","aliases":[],"title":"net/sched: sch_teql: fix use-after-free on lower qdisc drop","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_teql: fix use-after-free on lower qdisc drop\n\nThe issue: teql_master_xmit() tests the slave's ndo_start_xmit() return\nvalue against NETDEV_TX_OK alone. A slave that consumes the skb but\nreturns an error code (rc < NET_XMIT_MASK, e.g. NET_XMIT_DROP) is treated\nas if the skb were still owned, so the loop restores skb->dev and calls\n__skb_pull() on it. A VLAN slave returns the result of dev_queue_xmit()\nfrom its ndo_start_xmit() (propagated since cbbef5e18307), and when the\nlower qdisc drops the packet that value is NET_XMIT_DROP after the skb\nhas been freed, giving a use-after-free in teql_master_xmit().\n\nThe Fix: test for consumption with dev_xmit_complete(), which accepts\nNETDEV_TX_OK and every rc < NET_XMIT_MASK, matching other callers that\nneed to distinguish consumed results from busy. Only NETDEV_TX_OK keeps\nthe packet counted in tx_packets/tx_bytes and advances the slave; a\nconsumed result that is neither a success nor NET_XMIT_CN ends the\nattempt and is charged to tx_dropped, so lower-qdisc drops are no longer\nreported as good transmits. NET_XMIT_CN is counted like success because\nit can accompany acceptance of the current packet: pfifo_head_drop drops\nthe old head, enqueues the current skb and returns NET_XMIT_CN.\n\nConditions to recreate the bug:\nWith CONFIG_NET_SCH_TEQL,\nCONFIG_VLAN_8021Q and CONFIG_DUMMY enabled, add lkrdummy0 (dummy) and\nlkrvlan0 (VLAN id 37 on lkrdummy0); set a pfifo limit 0 root on lkrdummy0\nand a teql0 root on lkrvlan0; bring teql0 up with an address and send one\nUDP packet to it. The VLAN xmit returns NET_XMIT_DROP from the lower\nqdisc while holding a freed skb.","state":0,"publishedAt":"2026-11-07T14:08:47.978+00:00","modifiedAt":"2026-11-07T14:08:47.978+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/sched/sch_teql.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"572a9d7b6fc7f20f573664063324c086be310c42\",\n                            \"lessThan\": \"fc55d92ae6a4b2e7d062cad6d4c67f6b061d9cde\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"572a9d7b6fc7f20f573664063324c086be310c42\",\n                            \"lessThan\": \"2702ae318630787c640ec0d0403ffd9d95c43e9e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"572a9d7b6fc7f20f573664063324c086be310c42\",\n                            \"lessThan\": \"782d6bb8f9b8e9d8591181662222bf74cd3ecf79\",\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/sched/sch_teql.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"2.6.33\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"2.6.33\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.61\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3.2\",\n                            \"lessThanOrEqual\": \"7.3.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.4-rc1\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/fc55d92ae6a4b2e7d062cad6d4c67f6b061d9cde","https://git.kernel.org/stable/c/2702ae318630787c640ec0d0403ffd9d95c43e9e","https://git.kernel.org/stable/c/782d6bb8f9b8e9d8591181662222bf74cd3ecf79"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99282","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-99282","identifiers":["CVE-2026-99282"]},"retained":false,"historicalAffected":[]}],"coverage":[]}