CVE-2021-47187

System lockups via incorrect idle-state timings

Published Apr 10, 2024 · Updated May 11, 2026

In the Linux kernel on MSM8998 systems, a device-tree timing flaw allows local users to trigger lockups or sudden reboots. arch/arm64/boot/dts/qcom/msm8998.dtsi assigns CPU-sleep latency and miscalculated minimum-residency values to idle states that also collapse the L2 cache, whose timing requirements are longer. SoC instability occurs when CPU scaling makes cluster and L2 power collapse frequent; the reported consequence is limited to lockups and reboots.

CVSS severity5.5
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

In the Linux kernel on MSM8998 systems, a device-tree timing flaw allows local users to trigger lockups or sudden reboots. arch/arm64/boot/dts/qcom/msm8998.dtsi assigns CPU-sleep latency and miscalculated minimum-residency values to idle states that also collapse the L2 cache, whose timing requirements are longer. SoC instability occurs when CPU scaling makes cluster and L2 power collapse frequent; the reported consequence is limited to lockups and reboots.

The record

CVE
CVE-2021-47187
Published
Apr 10, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 10, 2024CVE publishedPublication date reported by the CVE source.
  2. May 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=5.3
  2. Affected versionversion=c3083c80b52c4e29b65ed838d2e66a91b13a3152 <118c826ef8b43efe0fda8faf419673707ee8c5e5
  3. Affected versionversion=c3083c80b52c4e29b65ed838d2e66a91b13a3152 <3f1dcaff642e75c1d2ad03f783fa8a3b1f56dd50
  4. Affected versionversion=c3083c80b52c4e29b65ed838d2e66a91b13a3152 <a14d7038ea201c5526375becfc43b9ba281b1e82
  5. Affected versionversion=c3083c80b52c4e29b65ed838d2e66a91b13a3152 <e52fecdd0c142b95c720683885b06ee3f0e065c8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.3; version=c3083c80b52c4e29b65ed838d2e66a91b13a3152 <118c826ef8b43efe0fda8faf419673707ee8c5e5; version=c3083c80b52c4e29b65ed838d2e66a91b13a3152 <3f1dcaff642e75c1d2ad03f783fa8a3b1f56dd50; version=c3083c80b52c4e29b65ed838d2e66a91b13a3152 <a14d7038ea201c5526375becfc43b9ba281b1e82; version=c3083c80b52c4e29b65ed838d2e66a91b13a3152 <e52fecdd0c142b95c720683885b06ee3f0e065c8

Published CVSS scores

5.5UbuntuCVSS: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

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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

No sourced classifications are available.

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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