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VulnerabilityPublished Updated

CVE-2026-74731: Linux kernel · sched_ext: Skip sub-disable teardown for never-linked sub-schedulers

Affects Linux kernelSource GCVE Database

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Not known to be exploited · CVSS 7.8 High.

Data as of 12 Nov 2026, 20:17 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 12 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
Ubuntu 24.04 LTSlinux-aws-6.14pkg:deb/ubuntu/linux-aws-6.14?arch=source&distro=nobleOther threatsAffected
  • 6.14.0-1007.7~24.04.1 – 6.14.0-1018.18~24.04.1
11 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-aws-6.17pkg:deb/ubuntu/linux-aws-6.17?arch=source&distro=nobleOther threatsAffected
  • 6.17.0-1005.5~24.04.2 – 6.17.0-1020.20~24.04.1
10 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threatsAffected
  • 6.11.0-1008.8~24.04.1 – 6.11.0-1018.18~24.04.1
7 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-azure-6.14pkg:deb/ubuntu/linux-azure-6.14?arch=source&distro=nobleOther threatsAffected
  • 6.14.0-1010.10~24.04.1 – 6.14.0-1017.17~24.04.1
5 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-azure-6.17pkg:deb/ubuntu/linux-azure-6.17?arch=source&distro=nobleOther threatsAffected
  • 6.17.0-1008.8~24.04.1 – 6.17.0-1022.22
10 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-azure-fde-6.14pkg:deb/ubuntu/linux-azure-fde-6.14?arch=source&distro=nobleOther threatsAffected
  • 6.14.0-1012.12~24.04.1 – 6.14.0-1017.17~24.04.1
5 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available that skips the sub-disable teardown steps for sub-schedulers that were never linked, preventing the use-after-free condition. Users should apply the official kernel updates that include this fix. Since this is a kernel-level vulnerability, updating to patched kernel versions is the recommended mitigation.

Description

A high-severity vulnerability in the Linux kernel scheduler (sched_ext) allows a use-after-free condition due to improper handling of sub-schedulers that never link into the scheduling hierarchy. This occurs when a sub-scheduler enable fails before linking, leading to a race condition during teardown that can cause tasks to be exited without a scheduler and then incorrectly re-homed, potentially resulting in system instability or compromise.

References

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