CVE-2026-89521Public exploit

System hang via stale core-scheduling selection state

Published Sep 11, 2026 · Updated Sep 11, 2026

Race condition in Linux 6.19 allows local users to hang the system through concurrent sched_ext core scheduling. In pick_next_task(), a pick_task() retry can release the run-queue lock while stale selection and force-idle state survives an interleaving core-wide selection. Exploitation requires SMT, core-scheduling cookies, and a loaded sched_ext scheduler; the resulting lock ping-pong can stop every CPU and require a hardware reset.

CVSS severityUnavailable
Unscored
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in Linux 6.19 allows local users to hang the system through concurrent sched_ext core scheduling. In pick_next_task(), a pick_task() retry can release the run-queue lock while stale selection and force-idle state survives an interleaving core-wide selection. Exploitation requires SMT, core-scheduling cookies, and a loaded sched_ext scheduler; the resulting lock ping-pong can stop every CPU and require a hardware reset.

The record

CVE
CVE-2026-89521
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4c95380701f58b8112f0b891de8d160e4199e19d <88ed5a66467ca2a5148b9997af9c71d8c43060ad
  2. Affected versionversion=4c95380701f58b8112f0b891de8d160e4199e19d <c10b216a072ff5c57bc880a05f87eb519aecc529
  3. Affected versionversion=6.19

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4c95380701f58b8112f0b891de8d160e4199e19d <88ed5a66467ca2a5148b9997af9c71d8c43060ad; version=4c95380701f58b8112f0b891de8d160e4199e19d <c10b216a072ff5c57bc880a05f87eb519aecc529; version=6.19

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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