CVE-2021-47090

Kernel panic via stale page-count flag

Published Mar 4, 2024 · Updated May 11, 2026

Reference-count error in affected Linux kernel versions allows local users to trigger a kernel panic through MADV_SOFT_OFFLINE. In mm/memory-failure.c, get_any_page() retains MF_COUNT_INCREASED on a retry even though the page reference count was not incremented, so release processing reaches a zero-count assertion. The path requires CONFIG_MEMORY_FAILURE and a soft-offline request that reaches the retry path; successful triggering crashes the host kernel rather than exposing or modifying data.

CVSS severity5.5
Medium
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reference-count error in affected Linux kernel versions allows local users to trigger a kernel panic through MADV_SOFT_OFFLINE. In mm/memory-failure.c, get_any_page() retains MF_COUNT_INCREASED on a retry even though the page reference count was not incremented, so release processing reaches a zero-count assertion. The path requires CONFIG_MEMORY_FAILURE and a soft-offline request that reaches the retry path; successful triggering crashes the host kernel rather than exposing or modifying data.

The record

CVE
CVE-2021-47090
Published
Mar 4, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 4, 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=5.10
  2. Affected versionversion=b94e02822debdf0cc473556aad7dcc859f216653 <1f207076740101fed87074a6bc924dbe806f08a5
  3. Affected versionversion=b94e02822debdf0cc473556aad7dcc859f216653 <2a57d83c78f889bf3f54eede908d0643c40d5418
  4. Affected versionversion=b94e02822debdf0cc473556aad7dcc859f216653 <c691e7575eff76e563b0199c23ec46bd454f43e3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.10; version=b94e02822debdf0cc473556aad7dcc859f216653 <1f207076740101fed87074a6bc924dbe806f08a5; version=b94e02822debdf0cc473556aad7dcc859f216653 <2a57d83c78f889bf3f54eede908d0643c40d5418; version=b94e02822debdf0cc473556aad7dcc859f216653 <c691e7575eff76e563b0199c23ec46bd454f43e3

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

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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