# CVE-2026-74731: linux: In the Linux kernel, the following vulnerability has been resolved:  sched_ext: Skip sub-disable teardown for never-l...

CVE-2026-74731 is fixed in linux on 1 platform by DEBIAN-CVE-2026-74731 (version 7.1.9-1), released September 4, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-74731
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0017
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 22, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.1.9-1 | [DEBIAN-CVE-2026-74731](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74731.md) | Sep 4, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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