{"id":"CVE-2026-72390","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-72390","summary":"net/sched: sch_teql: Introduce slaves_lock to avoid race condition and UAF","details":"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 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.","published":"2026-08-15T05:56:19.186Z","modified":"2026-08-16T03:48:41.093757059Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.1.178"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/03c67781254c574ae7fa75e881239a78473bdf42"},{"type":"WEB","url":"https://git.kernel.org/stable/c/11402e6e18e96df615cbcc58157818dd604b23ff"},{"type":"WEB","url":"https://git.kernel.org/stable/c/735567bde7401f82b064f9f107b52ee1bf84ed8c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9b7d05cbaa60108642402100efa6aa288dd33023"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b26aa9d993537a4c3167d8ceead3b7c69c3a0aac"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e5b811fe793166aecc59b085c1b7c31262ef2316"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72390.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72390"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-16T03:48:41.093757059Z"}}