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VulnerabilityPublished Updated

CVE-2026-89520: Linux kernel · sched/core: Make core-sched flips wait for in-flight selections

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in f3629c63a4af3e491381780bc6c123cb498c4c40 : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in f3629c63a4af3e491381780bc6c123cb498c4c40, a2a16896ed53046f275f56a6cd8ca3fb6f12c4f3, 23eda24f325a6e6d686d30ec75f2e9d6745e2015 +2
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 11 Sep 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

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 539f65125d20aacab54d02d77f10a839f45b09dc, < f3629c63a4af3e491381780bc6c123cb498c4c40
Fixed in
  • f3629c63a4af3e491381780bc6c123cb498c4c40
LinuxLinuxAffected
  • ≥ 539f65125d20aacab54d02d77f10a839f45b09dc, < a2a16896ed53046f275f56a6cd8ca3fb6f12c4f3
Fixed in
  • a2a16896ed53046f275f56a6cd8ca3fb6f12c4f3
LinuxLinuxAffected
  • ≥ 539f65125d20aacab54d02d77f10a839f45b09dc, < 23eda24f325a6e6d686d30ec75f2e9d6745e2015
Fixed in
  • 23eda24f325a6e6d686d30ec75f2e9d6745e2015
LinuxLinuxAffected
  • ≥ 539f65125d20aacab54d02d77f10a839f45b09dc, < 9d69422ddaa13526c2223444e237d948d6e44728
Fixed in
  • 9d69422ddaa13526c2223444e237d948d6e44728
LinuxLinuxAffected
  • ≥ 539f65125d20aacab54d02d77f10a839f45b09dc, < 3e2511bffa93a639774a99e392181e21d28677e2
Fixed in
  • 3e2511bffa93a639774a99e392181e21d28677e2
LinuxLinuxAffected
  • =5.14
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: sched/core: Make core-sched flips wait for in-flight selections Core scheduling's pick_next_task() operates on all sibling rqs under one acquisition of the shared core-wide lock. A ->pick_task() that releases the rq lock leaves every sibling __lock momentarily free, letting __sched_core_flip(false) complete mid-selection and rebind rq_lockp() under it. The selection resumes on the split locks, touching sibling state it no longer protects, and __schedule() finally releases a lock that was never taken while leaking the one that was. Count in-flight core-wide selections in the leader's rq->core_pick_in_flight and make __sched_core_flip() wait for the count to drain. The count only changes under the shared lock, which the flip holds while sampling, so no other ordering is needed. The wait can repeat while selections overlap, but the flip backs off between samples and flips are rare cookie-lifetime events. sched_core_cpu_deactivate() moves the count to the new leader - a stale copy left behind would bias it forever if that CPU later returns as its own leader.

References

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