CVE-2023-53187

Local kernel crash via missing block-group reference

Published Sep 15, 2025 · Updated Sep 15, 2025

Use-after-free in Linux btrfs allows local users to crash the kernel during cleanup of an unused new block group. btrfs_mark_bg_unused() moves a still-new block group to the unused list without taking the reference expected for a reclaimed group, so later cleanup decrements the reference count to zero. The demonstrated trigger requires local filesystem activity that creates and abandons a block group before creation finishes; unmount then reaches a kernel assertion and crash.

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

What happened

Use-after-free in Linux btrfs allows local users to crash the kernel during cleanup of an unused new block group. btrfs_mark_bg_unused() moves a still-new block group to the unused list without taking the reference expected for a reclaimed group, so later cleanup decrements the reference count to zero. The demonstrated trigger requires local filesystem activity that creates and abandons a block group before creation finishes; unmount then reaches a kernel assertion and crash.

The record

CVE
CVE-2023-53187
Published
Sep 15, 2025
Updated
Sep 15, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1499
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 15, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 15, 2025Record 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=01eca70ef8cf499d0cb6d1bbd691558e7792cf17 <6297644db23f77c02ae7961cc542d162629ae2c4
  2. Affected versionversion=5d19abcffd8404078dfa7d7118cec357b5e7bc58 <7569c4294ba6ff9f194635b14876198f8a687c4a
  3. Affected versionversion=a9f189716cf15913c453299d72f69c51a9b0f86b <0657b20c5a76c938612f8409735a8830d257866e
  4. Affected versionversion=edf3b5aadb2515c808200b904baa5b70a727f0ac

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=01eca70ef8cf499d0cb6d1bbd691558e7792cf17 <6297644db23f77c02ae7961cc542d162629ae2c4; version=5d19abcffd8404078dfa7d7118cec357b5e7bc58 <7569c4294ba6ff9f194635b14876198f8a687c4a; version=a9f189716cf15913c453299d72f69c51a9b0f86b <0657b20c5a76c938612f8409735a8830d257866e; version=edf3b5aadb2515c808200b904baa5b70a727f0ac

Published CVSS scores

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.

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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
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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