CVE-2026-43392

System hang via sched_ext enable-thread starvation

Published May 8, 2026 · Updated May 8, 2026

Denial of service in the Linux kernel sched_ext component allows local users to hang the system during scheduler enablement. The scx_enable() READY-to-ENABLED loop moves its caller from the fair class to the lower-priority ext class without preventing fair-class starvation. A local user able to enable sched_ext while fair-class workloads saturate the CPUs can indefinitely starve the enable thread and leave the system unresponsive.

CVSS severity5.5
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux kernel sched_ext component allows local users to hang the system during scheduler enablement. The scx_enable() READY-to-ENABLED loop moves its caller from the fair class to the lower-priority ext class without preventing fair-class starvation. A local user able to enable sched_ext while fair-class workloads saturate the CPUs can indefinitely starve the enable thread and leave the system unresponsive.

The record

CVE
CVE-2026-43392
Published
May 8, 2026
Updated
May 8, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-821, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 8, 2026CVE publishedPublication date reported by the CVE source.
  2. May 8, 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=6.12
  2. Affected versionversion=8c2090c504e998c8f34ec870bae71dafcc96a6e0 <05ab9ec5dc24f234e0a2fecf3e6ff937c68f7d81
  3. Affected versionversion=8c2090c504e998c8f34ec870bae71dafcc96a6e0 <b06ccbabe2506fd70b9167a644978b049150224a
  4. Affected versionversion=8c2090c504e998c8f34ec870bae71dafcc96a6e0 <c44198f25fdfecc0ec0fe366bf8a47fe17d8e229
  5. Affected versionversion=8c2090c504e998c8f34ec870bae71dafcc96a6e0 <e0b14bf06393be137d3efb6a3b7cd5b4b9810a6b

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.12; version=8c2090c504e998c8f34ec870bae71dafcc96a6e0 <05ab9ec5dc24f234e0a2fecf3e6ff937c68f7d81; version=8c2090c504e998c8f34ec870bae71dafcc96a6e0 <b06ccbabe2506fd70b9167a644978b049150224a; version=8c2090c504e998c8f34ec870bae71dafcc96a6e0 <c44198f25fdfecc0ec0fe366bf8a47fe17d8e229; version=8c2090c504e998c8f34ec870bae71dafcc96a6e0 <e0b14bf06393be137d3efb6a3b7cd5b4b9810a6b

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-821Incorrect Synchronization
T1499.004Application or System Exploitation

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

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Your stack

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