CVE-2021-47094

Kernel memory corruption via skipped shadow-page entries

Published Mar 4, 2024 · Updated Aug 5, 2026

A use-after-free in Linux KVM allows local users to corrupt kernel memory during TDP MMU teardown by destroying a virtual machine. After yielding, tdp_iter_next advances a restarted iterator, skips an unvisited top-level SPTE, and later marks an already freed page dirty or accessed. Affected releases are 5.10 through 5.15.11 and 5.16-rc1 through 5.16-rc6; KVM access is required, and outcomes include leaked shadow pages, warnings, or data corruption.

CVSS severity7.1
High
EPSS probability0.22%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A use-after-free in Linux KVM allows local users to corrupt kernel memory during TDP MMU teardown by destroying a virtual machine. After yielding, tdp_iter_next advances a restarted iterator, skips an unvisited top-level SPTE, and later marks an already freed page dirty or accessed. Affected releases are 5.10 through 5.15.11 and 5.16-rc1 through 5.16-rc6; KVM access is required, and outcomes include leaked shadow pages, warnings, or data corruption.

The record

CVE
CVE-2021-47094
Published
Mar 4, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 4, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=5.10
  2. Affected versionversion=faaf05b00aecdb347ffd1d763d024394ec0329f8 <3a0f64de479cae75effb630a2e0a237ca0d0623c
  3. Affected versionversion=faaf05b00aecdb347ffd1d763d024394ec0329f8 <d884eefd75cc54887bc2e9e724207443525dfb2c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.10; version=faaf05b00aecdb347ffd1d763d024394ec0329f8 <3a0f64de479cae75effb630a2e0a237ca0d0623c; version=faaf05b00aecdb347ffd1d763d024394ec0329f8 <d884eefd75cc54887bc2e9e724207443525dfb2c

Published CVSS scores

7.1CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 11, 2026Sep 17, 2026
Latest reporting daySep 17, 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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