CVE-2021-46950

Data corruption via cleared failed-write bitmap bits

Published Feb 27, 2024 · Updated May 23, 2026

Data corruption in Linux kernel RAID1 arrays using bitmaps allows local users to corrupt mirrored data when a write request fails. The raid1_end_write_request failure path clears the failed I/O's bitmap bits instead of retaining them for retry or marking the request degraded. The condition requires a bitmap-enabled RAID1 array and a failed write; cleared bits can prevent resynchronization from repairing the stale mirror leg.

CVSS severity7.8
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Data corruption in Linux kernel RAID1 arrays using bitmaps allows local users to corrupt mirrored data when a write request fails. The raid1_end_write_request failure path clears the failed I/O's bitmap bits instead of retaining them for retry or marking the request degraded. The condition requires a bitmap-enabled RAID1 array and a failed write; cleared bits can prevent resynchronization from repairing the stale mirror leg.

The record

CVE
CVE-2021-46950
Published
Feb 27, 2024
Updated
May 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1565.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 2024CVE publishedPublication date reported by the CVE source.
  2. May 23, 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=1cd972e0a10760a1fa27d9830d78446c891c23b6 <a6e17cab00fc5bf85472434c52ac751426257c6f
  2. Affected versionversion=344242d50f468a250bf4b6136934392758412ed8
  3. Affected versionversion=4.14.147 <4.14.233
  4. Affected versionversion=4.19.77 <4.19.191
  5. Affected versionversion=5.2.19 <5.3
  6. Affected versionversion=5.3.4 <5.4
  7. Affected versionversion=5.4
  8. Affected versionversion=900c531899f5ee2321bef79e20055787bc73251d <12216d0919b64ee2ea5dc7a50e455670f44383d5
  9. Affected versionversion=a1f4fcb880988a96c0b2d5c3305ffc4e49eca0ed
  10. Affected versionversion=eeba6809d8d58908b5ed1b5ceb5fcb09a98a7cad <2417b9869b81882ab90fd5ed1081a1cb2d4db1dd
  11. Affected versionversion=eeba6809d8d58908b5ed1b5ceb5fcb09a98a7cad <538244fba59fde17186322776247cd9c05be86dd
  12. Affected versionversion=eeba6809d8d58908b5ed1b5ceb5fcb09a98a7cad <59452e551784b7a57a45d971727e9db63b192515
  13. Affected versionversion=eeba6809d8d58908b5ed1b5ceb5fcb09a98a7cad <661061a45e32d8b2cc0e306da9f169ad44011382
  14. Affected versionversion=eeba6809d8d58908b5ed1b5ceb5fcb09a98a7cad <6920cef604fa57f9409e3960413e9cc11f5c5a40

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1cd972e0a10760a1fa27d9830d78446c891c23b6 <a6e17cab00fc5bf85472434c52ac751426257c6f; version=344242d50f468a250bf4b6136934392758412ed8; version=4.14.147 <4.14.233; version=4.19.77 <4.19.191; version=5.2.19 <5.3; version=5.3.4 <5.4; version=5.4; version=900c531899f5ee2321bef79e20055787bc73251d <12216d0919b64ee2ea5dc7a50e455670f44383d5; version=a1f4fcb880988a96c0b2d5c3305ffc4e49eca0ed; version=eeba6809d8d58908b5ed1b5ceb5fcb09a98a7cad <2417b9869b81882ab90fd5ed1081a1cb2d4db1dd; version=eeba6809d8d58908b5ed1b5ceb5fcb09a98a7cad <538244fba59fde17186322776247cd9c05be86dd; version=eeba6809d8d58908b5ed1b5ceb5fcb09a98a7cad <59452e551784b7a57a45d971727e9db63b192515; version=eeba6809d8d58908b5ed1b5ceb5fcb09a98a7cad <661061a45e32d8b2cc0e306da9f169ad44011382; version=eeba6809d8d58908b5ed1b5ceb5fcb09a98a7cad <6920cef604fa57f9409e3960413e9cc11f5c5a40

Published CVSS scores

7.8CISA ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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

T1565.001Stored Data Manipulation

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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