CVE-2026-43227

Local service interruption via incompatible spinlock contexts

Published May 6, 2026 · Updated May 6, 2026

Lock-context misuse in the Linux kernel sh_tmu driver allows local users to interrupt service on affected PREEMPT_RT systems. While the clockevent framework holds a raw spinlock, sh_tmu calls runtime-power and clock APIs whose platform paths take sleep-capable regular spinlocks, producing an invalid wait context. Reachability requires a PREEMPT_RT kernel using the TMU as a clockevent provider; non-PREEMPT_RT builds are not materially affected, and the reported consequence is availability loss only.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Lock-context misuse in the Linux kernel sh_tmu driver allows local users to interrupt service on affected PREEMPT_RT systems. While the clockevent framework holds a raw spinlock, sh_tmu calls runtime-power and clock APIs whose platform paths take sleep-capable regular spinlocks, producing an invalid wait context. Reachability requires a PREEMPT_RT kernel using the TMU as a clockevent provider; non-PREEMPT_RT builds are not materially affected, and the reported consequence is availability loss only.

The record

CVE
CVE-2026-43227
Published
May 6, 2026
Updated
May 6, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 6, 2026CVE publishedPublication date reported by the CVE source.
  2. May 6, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <016476afef993d1201a19decc9b5b2ea1e6620f2
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <0e513cc6b9cea190fe342cc222b1054e7e8acfc8
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6f113ab549b864c1bc57d4f89846ee335394089a
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <79d650695773f03de36b99228a090d33d1c18264
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <88c76792180dffd83f1c5b9dc8fdaeb145cb94e0
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b1278972b08e480990e2789bdc6a7c918bc349be
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <bc59d5f3afe41fec5d673c27c703b761ae578d28
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f0b31247e7d67a943b3a09d3cef7c0ae788d88e6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <016476afef993d1201a19decc9b5b2ea1e6620f2; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <0e513cc6b9cea190fe342cc222b1054e7e8acfc8; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6f113ab549b864c1bc57d4f89846ee335394089a; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <79d650695773f03de36b99228a090d33d1c18264; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <88c76792180dffd83f1c5b9dc8fdaeb145cb94e0; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b1278972b08e480990e2789bdc6a7c918bc349be; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <bc59d5f3afe41fec5d673c27c703b761ae578d28; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f0b31247e7d67a943b3a09d3cef7c0ae788d88e6

Published CVSS scores

5.5NVDCVSS: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

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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