CVE-2021-47110

Memory corruption via boot-CPU-only kvmclock shutdown

Published Mar 15, 2024 · Updated May 11, 2026

Memory corruption in the Linux kernel allows attackers to corrupt memory when a KVM guest resumes after hibernation. The machine_shutdown hook disables kvmclock only on the boot CPU, allowing secondary CPUs to keep updating a shared clock memory location after shutdown. Reachability requires an x86 Linux KVM guest and a shutdown followed by hibernation restore; published evidence bounds the result to memory corruption and does not establish code execution.

CVSS severityUnavailable
Unscored
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in the Linux kernel allows attackers to corrupt memory when a KVM guest resumes after hibernation. The machine_shutdown hook disables kvmclock only on the boot CPU, allowing secondary CPUs to keep updating a shared clock memory location after shutdown. Reachability requires an x86 Linux KVM guest and a shutdown followed by hibernation restore; published evidence bounds the result to memory corruption and does not establish code execution.

The record

CVE
CVE-2021-47110
Published
Mar 15, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Mar 15, 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=1e977aa12dd4f80688b1f243762212e75c6d7fe8 <1df2dc09926f61319116c80ee85701df33577d70
  2. Affected versionversion=1e977aa12dd4f80688b1f243762212e75c6d7fe8 <3b0becf8b1ecf642a9edaf4c9628ffc641e490d6
  3. Affected versionversion=1e977aa12dd4f80688b1f243762212e75c6d7fe8 <9084fe1b3572664ad276f427dce575f580c9799a
  4. Affected versionversion=1e977aa12dd4f80688b1f243762212e75c6d7fe8 <c02027b5742b5aa804ef08a4a9db433295533046
  5. Affected versionversion=2.6.26

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=1e977aa12dd4f80688b1f243762212e75c6d7fe8 <1df2dc09926f61319116c80ee85701df33577d70; version=1e977aa12dd4f80688b1f243762212e75c6d7fe8 <3b0becf8b1ecf642a9edaf4c9628ffc641e490d6; version=1e977aa12dd4f80688b1f243762212e75c6d7fe8 <9084fe1b3572664ad276f427dce575f580c9799a; version=1e977aa12dd4f80688b1f243762212e75c6d7fe8 <c02027b5742b5aa804ef08a4a9db433295533046; version=2.6.26

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)
VectorUnavailable
PrivilegesUnavailable
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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