CVE-2021-47066

RAID5 data corruption via mismatched source offsets

Published Feb 29, 2024 · Updated Aug 5, 2026

Data corruption in the Linux kernel allows local users to corrupt RAID5 data through ordinary writes to an affected array. In ops_run_prexor5, dropping the destination advances src_list without advancing the parallel src_offs entry, so async_xor reads a mismatched in-page offset and calculates incorrect parity. The path requires RAID5 read-modify-write processing with shared pages when PAGE_SIZE differs from the stripe size, and corruption can leave the filesystem unmountable.

CVSS severity7.1
High
EPSS probability0.23%
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 the Linux kernel allows local users to corrupt RAID5 data through ordinary writes to an affected array. In ops_run_prexor5, dropping the destination advances src_list without advancing the parallel src_offs entry, so async_xor reads a mismatched in-page offset and calculates incorrect parity. The path requires RAID5 read-modify-write processing with shared pages when PAGE_SIZE differs from the stripe size, and corruption can leave the filesystem unmountable.

The record

CVE
CVE-2021-47066
Published
Feb 29, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1485
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 29, 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=29bcff787a2593b2126cfaff612c0b4e560022e9 <29ffa50f33de824b5491f8239c88c4a0efdd03af
  2. Affected versionversion=29bcff787a2593b2126cfaff612c0b4e560022e9 <53f8208e11abd6dde9480dfcb97fecdb1bc2ac18
  3. Affected versionversion=29bcff787a2593b2126cfaff612c0b4e560022e9 <cab2e8e5997b592fdb7d02cf2387b4b8e3057174
  4. Affected versionversion=29bcff787a2593b2126cfaff612c0b4e560022e9 <ceaf2966ab082bbc4d26516f97b3ca8a676e2af8
  5. Affected versionversion=5.10

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=29bcff787a2593b2126cfaff612c0b4e560022e9 <29ffa50f33de824b5491f8239c88c4a0efdd03af; version=29bcff787a2593b2126cfaff612c0b4e560022e9 <53f8208e11abd6dde9480dfcb97fecdb1bc2ac18; version=29bcff787a2593b2126cfaff612c0b4e560022e9 <cab2e8e5997b592fdb7d02cf2387b4b8e3057174; version=29bcff787a2593b2126cfaff612c0b4e560022e9 <ceaf2966ab082bbc4d26516f97b3ca8a676e2af8; version=5.10

Published CVSS scores

7.1kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
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

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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

T1485Data Destruction

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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