CVE-2021-47113

Filesystem disruption via incomplete inode-reference exchange

Published Mar 15, 2024 · Updated Aug 5, 2026

Denial of service in Linux kernel btrfs allows local users to disrupt a mounted filesystem through an exchanged rename after insertion failure. The btrfs_rename_exchange path inserts one inode reference before its peer and fails to abort the transaction when the second insertion fails, allowing a dangling reference to persist. Reachability requires local rename permissions on a mounted btrfs filesystem, and the published assessment identifies availability loss without disclosed data-reading or data-writing capability.

CVSS severity5.5
Medium
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

Denial of service in Linux kernel btrfs allows local users to disrupt a mounted filesystem through an exchanged rename after insertion failure. The btrfs_rename_exchange path inserts one inode reference before its peer and fails to abort the transaction when the second insertion fails, allowing a dangling reference to persist. Reachability requires local rename permissions on a mounted btrfs filesystem, and the published assessment identifies availability loss without disclosed data-reading or data-writing capability.

The record

CVE
CVE-2021-47113
Published
Mar 15, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 15, 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=4.7
  2. Affected versionversion=cdd1fedf8261cd7a73c0596298902ff4f0f04492 <0df50d47d17401f9f140dfbe752a65e5d72f9932
  3. Affected versionversion=cdd1fedf8261cd7a73c0596298902ff4f0f04492 <dc09ef3562726cd520c8338c1640872a60187af5
  4. Affected versionversion=cdd1fedf8261cd7a73c0596298902ff4f0f04492 <ff8de2cec65a8c8521faade12a31b39c80e49f5b

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.7; version=cdd1fedf8261cd7a73c0596298902ff4f0f04492 <0df50d47d17401f9f140dfbe752a65e5d72f9932; version=cdd1fedf8261cd7a73c0596298902ff4f0f04492 <dc09ef3562726cd520c8338c1640872a60187af5; version=cdd1fedf8261cd7a73c0596298902ff4f0f04492 <ff8de2cec65a8c8521faade12a31b39c80e49f5b

Published CVSS scores

5.5UbuntuCVSS: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.

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

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.

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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