CVE-2021-47343

System crash via uninitialized dm-btree root

Published May 21, 2024 · Updated Aug 5, 2026

Out-of-bounds memory access in Linux allows local users to crash the system through a failed dm-thin metadata removal. When remove_raw() fails during shadowing after an I/O read error, dm_btree_remove() copies the uninitialized shadow_spine::root into new_root, corrupting the stored dm-thin tree root. Local access to device-mapper control operations and a removal-time read failure are required; rereading the tree can raise a general protection fault.

CVSS severity7.8
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds memory access in Linux allows local users to crash the system through a failed dm-thin metadata removal. When remove_raw() fails during shadowing after an I/O read error, dm_btree_remove() copies the uninitialized shadow_spine::root into new_root, corrupting the stored dm-thin tree root. Local access to device-mapper control operations and a removal-time read failure are required; rereading the tree can raise a general protection fault.

The record

CVE
CVE-2021-47343
Published
May 21, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-1188, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 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=3.2
  2. Affected versionversion=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <4c84b3e0728ffe10d89c633694c35a02b5c477dc
  3. Affected versionversion=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <73f27adaa73e3057a9ec464e33c4f54d34ea5de3
  4. Affected versionversion=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <89bf942314b78d454db92427201421b5dec132d9
  5. Affected versionversion=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <8fbae4a1bdb5b889490cdee929e68540151536e5
  6. Affected versionversion=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <964d57d1962d7e68f0f578f05d9ae4a104d74851
  7. Affected versionversion=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <ad365e9351ac2b450e7e79932ff6abf59342d91a
  8. Affected versionversion=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <b6e58b5466b2959f83034bead2e2e1395cca8aeb
  9. Affected versionversion=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <ba47e65a5de3e0e8270301a409fc63d3129fdb9e
  10. Affected versionversion=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <c154775619186781aaf8a99333ac07437a1768d5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3.2; version=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <4c84b3e0728ffe10d89c633694c35a02b5c477dc; version=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <73f27adaa73e3057a9ec464e33c4f54d34ea5de3; version=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <89bf942314b78d454db92427201421b5dec132d9; version=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <8fbae4a1bdb5b889490cdee929e68540151536e5; version=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <964d57d1962d7e68f0f578f05d9ae4a104d74851; version=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <ad365e9351ac2b450e7e79932ff6abf59342d91a; version=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <b6e58b5466b2959f83034bead2e2e1395cca8aeb; version=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <ba47e65a5de3e0e8270301a409fc63d3129fdb9e; version=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <c154775619186781aaf8a99333ac07437a1768d5

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.8kernel.orgCVSS: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

CWE-1188Insecure Default Initialization of Resource
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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