---
id: CVE-2026-74731
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sched_ext: Skip sub-disable teardown for never-linked sub-schedulers

  A sub-scheduler enable can fail before scx_link_sched() links the sched into
  the hierarchy, e.g
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sched_ext: Skip sub-disable teardown for never-linked sub-schedulers

  A sub-scheduler enable can fail before scx_link_sched() links the sched into
  the hierarchy, e.g. w…
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'
published: '2026-08-22'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T13:10:00.187'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74731'
references:
  - url: 'https://git.kernel.org/stable/c/6428093a4a986c38c9089b5eb32b56d914ef437a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8c13364db9c9a43ed286f3a8d0fb9477b1adc43c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00165
epssPercentile: 0.05281
ingestedAt: '2026-10-14T13:30:58.550Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

sched_ext: Skip sub-disable teardown for never-linked sub-schedulers

A sub-scheduler enable can fail before scx_link_sched() links the sched into
the hierarchy, e.g. when the parent is already being disabled, and cleanup
still runs the full scx_sub_disable().

That is racy against root disable: drain_descendants() is the only ordering
between a sub's disable-time task walk and root disable's all-task teardown,
and an unlinked sub is invisible to it. Root's teardown can thus run between
the never-linked sub's drain and its walk, exiting every task to no
scheduler.

The walk then trips the membership WARN and re-homes the exited tasks onto
the dying hierarchy, a use-after-free.

Skip the cgroup ownership reset and the task walk if @sch was never linked,
indicated by the empty ->sibling as unlinking only happens later in the same
function. The membership WARN remains valid: a linked sub is always waited
on by an ancestor's drain.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.