VulnerabilityPublished 11 Sep 2026Updated 5 Oct 2026

CVE-2026-89519: Linux kernel · sched_ext: Replace SCX_RQ_BAL_KEEP with a dispatch verdict return

Affects Linux kernelSource GCVE Database

Not known to be exploited.

Data as of 26 Oct 2026, 12:55 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
CVE published 11 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-4vmj-w324-pvrj

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=resolute`Other threats	Affected 6.17.0-5.5 – 7.0.0-38.38 23 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1014.14 15 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=resolute`Other threats	Affected 6.17.0-1003.3 – 7.0.0-1017.17 15 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resolute`Other threats	Affected 7.0.0-1003.3 – 7.0.0-1016.16 9 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1014.14 13 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gke`pkg:deb/ubuntu/linux-gke?arch=source&distro=resolute`Other threats	Affected 7.0.0-1002.3 – 7.0.0-1008.9 6 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 has been implemented in the Linux kernel to address this issue by replacing the SCX_RQ_BAL_KEEP flag with an explicit dispatch verdict return. Users should apply the updated kernel versions that include this fix. Since this is a kernel-level fix, upgrading to the patched kernel versions listed is the recommended remediation.

Description

A vulnerability in the Linux kernel's core scheduling subsystem related to the handling of the SCX_RQ_BAL_KEEP flag has been resolved. The issue involved the flag being used incorrectly when dispatches and picks no longer paired one-to-one, potentially causing a task to continue running after it was dequeued. The fix replaces the flag with an explicit dispatch verdict return to ensure correct scheduling decisions. This vulnerability affects specific Linux kernel versions used in various Ubuntu HWE edge releases.

Impact

The vulnerability could cause the scheduler to incorrectly keep running a task that has been dequeued, potentially leading to scheduling inconsistencies or unexpected behavior in task execution. There is no indication of active exploitation or direct security compromise from the provided data.

Summary

The Linux kernel vulnerability CVE-2026-89519 concerns the sched_ext subsystem where the SCX_RQ_BAL_KEEP flag was improperly used to indicate that the scheduler should keep running the previous task. This flag was a leftover from when balancing and picking tasks were separate operations and assumed a one-to-one pairing of dispatch and pick operations. Core scheduling breaks this assumption because selections interleave through dispatch's lock drops, allowing a pick operation to consume a stale flag and keep running a task that has already been dequeued. The fix involves changing the scheduling functions to return an explicit dispatch verdict instead of relying on the flag, removing the flag's plumbing from the tools autogen enum headers, and refactoring the pick-side invocation and related queueing logic. No functional changes beyond the fix were intended.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Oct 2026, 01:57 UTC

Technical details

References

Community reviews

Related threats