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VulnerabilityPublished Updated

CVE-2026-98864: Linux kernel · sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task

Affects Linux kernelSource GCVE Database

0
Authoritative record:CVE-2026-98864· Medium

Not known to be exploited · CVSS 5.7 Medium.

Data as of 28 Oct 2026, 22:29 UTC

CVSS 4.0 base score
5.7Medium
How severe the flaw is on the 0–10 CVSS scale.
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 18 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: 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 26 Oct 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.

Description

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task ebf1ccff79c4 ("sched_ext: Fix ops.dequeue() semantics") moved the final ops_state store in scx_dispatch_enqueue() after the DSQ unlock so that the custody update and ops.dequeue() precede it. A task can thus be found on a DSQ while still SCX_OPSS_DISPATCHING. The dequeue and core-sched pick paths wait for the state to clear in ops_dequeue() but the reenqueue paths don't. A reenqueue in that window runs ops.enqueue() and sets SCX_OPSS_QUEUED before the dispatch has completed. The dispatcher's final store then overwrites it with SCX_OPSS_NONE and finish_dispatch() drops every later dispatch of the task. Wait for SCX_OPSS_DISPATCHING to clear before dequeueing a task for reenqueue, the same way ops_dequeue() does.

References

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