CVE-2026-74731
sched_ext: Skip sub-disable teardown for never-linked sub-schedulers
Description
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.
INFO
Published Date :
Aug. 22, 2026, 4:16 p.m.
Last Modified :
Oct. 14, 2026, 1:10 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Update the Linux kernel to the latest stable version.
- Verify scheduler configuration and parent linkage.
- Monitor system stability after applying updates.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-74731.
| URL | Resource |
|---|---|
| https://git.kernel.org/stable/c/6428093a4a986c38c9089b5eb32b56d914ef437a | |
| https://git.kernel.org/stable/c/8c13364db9c9a43ed286f3a8d0fb9477b1adc43c |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-74731 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-74731
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-74731 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-74731 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Translated by [email protected]
Oct. 14, 2026
Action Type Old Value New Value Added Translation Title: Linux, Description: En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta: sched_ext: Omitir el desmantelamiento de sub-desactivación para sub-planificadores nunca vinculados Una activación de sub-planificador puede fallar antes de que scx_link_sched() vincule el planificador a la jerarquía, por ejemplo, cuando el padre ya está siendo deshabilitado, y la limpieza aún ejecuta el scx_sub_disable() completo. Eso es una condición de carrera contra la desactivación de la raíz: drain_descendants() es el único ordenamiento entre un recorrido de tareas en tiempo de desactivación de un sub y el desmantelamiento de todas las tareas de la desactivación de la raíz, y un sub desvinculado es invisible para ello. El desmantelamiento de la raíz puede, por lo tanto, ejecutarse entre el drenaje del sub nunca vinculado y su recorrido, haciendo que cada tarea salga a ningún planificador. El recorrido entonces activa la ADVERTENCIA de membresía y reasigna las tareas que salieron a la jerarquía moribunda, un uso después de liberación. Omitir el restablecimiento de la propiedad del cgroup y el recorrido de tareas si @sch nunca fue vinculado, indicado por el -> sibling vacío ya que la desvinculación solo ocurre más tarde en la misma función. La ADVERTENCIA de membresía sigue siendo válida: un sub vinculado siempre es esperado por el drenaje de un ancestro. -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 25, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 22, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '337ec00b1d9c676f637651c2cefddb8612b867ee', 'lessThan': '6428093a4a986c38c9089b5eb32b56d914ef437a', 'versionType': 'git'}, {'status': 'affected', 'version': '337ec00b1d9c676f637651c2cefddb8612b867ee', 'lessThan': '8c13364db9c9a43ed286f3a8d0fb9477b1adc43c', 'versionType': 'git'}], 'programFiles': ['kernel/sched/ext/ext.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '7.1'}, {'status': 'unaffected', 'version': '0', 'lessThan': '7.1', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '7.1.9', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['kernel/sched/ext/ext.c'], 'defaultStatus': 'affected'}] Added Description 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. Added Reference https://git.kernel.org/stable/c/6428093a4a986c38c9089b5eb32b56d914ef437a Added Reference https://git.kernel.org/stable/c/8c13364db9c9a43ed286f3a8d0fb9477b1adc43c