System hang via core-scheduler lock corruption
Published Sep 11, 2026 · Updated Sep 11, 2026
Race condition in the Linux core scheduler allows local users to hang the system through concurrent scheduler operations. A lock-dropping pick_task operation lets __sched_core_flip rebind runqueue locks during an in-flight sibling selection, so scheduling resumes while sibling state is unprotected and __schedule releases the wrong lock. Exposure requires CONFIG_SCHED_CORE and an overlap between a core-wide task selection and a core-scheduling flip; successful triggering wedges the host.
Summary
What happened
Race condition in the Linux core scheduler allows local users to hang the system through concurrent scheduler operations. A lock-dropping pick_task operation lets __sched_core_flip rebind runqueue locks during an in-flight sibling selection, so scheduling resumes while sibling state is unprotected and __schedule releases the wrong lock. Exposure requires CONFIG_SCHED_CORE and an overlap between a core-wide task selection and a core-scheduling flip; successful triggering wedges the host.
The record
- CVE
- CVE-2026-89520
- Published
- Sep 11, 2026
- Updated
- Sep 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 11, 2026CVE publishedPublication date reported by the CVE source.
- Sep 11, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=5.14
- Affected versionversion=539f65125d20aacab54d02d77f10a839f45b09dc <23eda24f325a6e6d686d30ec75f2e9d6745e2015
- Affected versionversion=539f65125d20aacab54d02d77f10a839f45b09dc <9d69422ddaa13526c2223444e237d948d6e44728
- Affected versionversion=539f65125d20aacab54d02d77f10a839f45b09dc <f3629c63a4af3e491381780bc6c123cb498c4c40
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo