{"id":"CVE-2026-72390","title":"net/sched: sch_teql: Introduce slaves_lock to avoid race condition and UAF","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_teql: Introduce slaves_lock to avoid race condition and UAF\n\nThe teql master->slaves singly linked list is not protected against\nmultiple writes. It can …","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 03c67781254c574ae7fa75e881239a78473bdf42","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 735567bde7401f82b064f9f107b52ee1bf84ed8c","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 11402e6e18e96df615cbcc58157818dd604b23ff","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 9b7d05cbaa60108642402100efa6aa288dd33023","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b26aa9d993537a4c3167d8ceead3b7c69c3a0aac","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e5b811fe793166aecc59b085c1b7c31262ef2316","Linux 2.6.12"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T18:48:26.249891Z"},"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T18:55:21.250Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72390","references":[{"url":"https://git.kernel.org/stable/c/03c67781254c574ae7fa75e881239a78473bdf42"},{"url":"https://git.kernel.org/stable/c/735567bde7401f82b064f9f107b52ee1bf84ed8c"},{"url":"https://git.kernel.org/stable/c/11402e6e18e96df615cbcc58157818dd604b23ff"},{"url":"https://git.kernel.org/stable/c/9b7d05cbaa60108642402100efa6aa288dd33023"},{"url":"https://git.kernel.org/stable/c/b26aa9d993537a4c3167d8ceead3b7c69c3a0aac"},{"url":"https://git.kernel.org/stable/c/e5b811fe793166aecc59b085c1b7c31262ef2316"}],"tags":["cve.org"],"epss":0.00174,"epssPercentile":0.06419,"ingestedAt":"2026-10-16T19:46:24.401Z","slug":"CVE-2026-72390","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_teql: Introduce slaves_lock to avoid race condition and UAF\n\nThe teql master->slaves singly linked list is not protected against\nmultiple writes. It can be mod'ed concurently from teql_master_xmit(),\nteql_dequeue(), teql_init() and teql_destroy() without holding any list\nlock or RCU protection.\n\nzdi-disclosures@trendmicro.com has demonstrated that the qdisc is freed\nafter an RCU grace period, but teql_master_xmit() running on another\nCPU can still hold a stale pointer into the list, resulting in a\nslab-use-after-free:\n\nBUG: KASAN: slab-use-after-free in teql_master_xmit+0xf0f/0x16b0\nRead of size 8 at addr ffff888013fb0440 by task poc/332\nFreed 512-byte region [ffff888013fb0400, ffff888013fb0600) (kmalloc-512)\n\nThe fix?\nAdd a per-master slaves_lock spinlock that serializes all mutations of\nmaster->slaves and the NEXT_SLAVE() links in teql_destroy() and\nteql_qdisc_init(). teql_master_xmit() also takes the same slaves_lock\naround those updates.\nAnnotate master->slaves and the per-slave ->next pointer with __rcu and\nuse the appropriate RCU accessors everywhere they are touched:\nrcu_assign_pointer() on the writer side (under slaves_lock),\nrcu_dereference_protected() for the writer-side loads (also under\nslaves_lock), rcu_dereference_bh() for the loads in teql_master_xmit() and\nrtnl_dereference() for the loads in teql_master_open()/teql_master_mtu(),\nwhich run under RTNL.\nPair this with rcu_read_lock_bh()/rcu_read_unlock_bh() around the list\ntraversal in teql_master_xmit(), so that readers either observe a fully\nlinked list or are deferred until the in-flight mutation completes. The two\nearly-return paths in teql_master_xmit() are updated to release the RCU-bh\nread-side critical section before returning, since leaving it held would\ndisable BH on that CPU for good.\n\n## Affected\n\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 03c67781254c574ae7fa75e881239a78473bdf42`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 735567bde7401f82b064f9f107b52ee1bf84ed8c`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 11402e6e18e96df615cbcc58157818dd604b23ff`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 9b7d05cbaa60108642402100efa6aa288dd33023`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b26aa9d993537a4c3167d8ceead3b7c69c3a0aac`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e5b811fe793166aecc59b085c1b7c31262ef2316`\n- `Linux 2.6.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}