{"id":"CVE-2026-74731","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-74731","summary":"sched_ext: Skip sub-disable teardown for never-linked sub-schedulers","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Skip sub-disable teardown for never-linked sub-schedulers\n\nA sub-scheduler enable can fail before scx_link_sched() links the sched into\nthe hierarchy, e.g. when the parent is already being disabled, and cleanup\nstill runs the full scx_sub_disable().\n\nThat is racy against root disable: drain_descendants() is the only ordering\nbetween a sub's disable-time task walk and root disable's all-task teardown,\nand an unlinked sub is invisible to it. Root's teardown can thus run between\nthe never-linked sub's drain and its walk, exiting every task to no\nscheduler.\n\nThe walk then trips the membership WARN and re-homes the exited tasks onto\nthe dying hierarchy, a use-after-free.\n\nSkip the cgroup ownership reset and the task walk if @sch was never linked,\nindicated by the empty ->sibling as unlinking only happens later in the same\nfunction. The membership WARN remains valid: a linked sub is always waited\non by an ancestor's drain.","published":"2026-08-22T15:33:20.294Z","modified":"2026-08-24T11:47:22.598849891Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"7.1.9"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/6428093a4a986c38c9089b5eb32b56d914ef437a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8c13364db9c9a43ed286f3a8d0fb9477b1adc43c"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74731.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74731"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-24T11:47:22.598849891Z"}}