CVE-2024-42103

Kernel crash via Btrfs block-group list race

Published Jul 30, 2024 · Updated Aug 5, 2026

Race condition in Btrfs block-group reclaim in affected Linux kernels allows local users to crash the kernel during relocation. The btrfs_reclaim_bgs_work path can re-add a relocating block group to the reclaim list while another path adds it to the unused list without holding fs_info->unused_bgs_lock, corrupting the shared list head. Write access to a mounted Btrfs filesystem is required, and the observed crash occurs when relocation exhausts chunk space and returns ENOSPC.

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

Race condition in Btrfs block-group reclaim in affected Linux kernels allows local users to crash the kernel during relocation. The btrfs_reclaim_bgs_work path can re-add a relocating block group to the reclaim list while another path adds it to the unused list without holding fs_info->unused_bgs_lock, corrupting the shared list head. Write access to a mounted Btrfs filesystem is required, and the observed crash occurs when relocation exhausts chunk space and returns ENOSPC.

The record

CVE
CVE-2024-42103
Published
Jul 30, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 30, 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=15cb476ceb7da730857b8e94f06161273adb7a3a <aa1d8cc0cc500e06b316cd6732d4e6c1388fe33c
  2. Affected versionversion=2311fd03027d2c1b2ac4a3a41153a16352659b65 <522b39bd7163e8dc49f8cf10b9b782218ac48746
  3. Affected versionversion=4eb4e85c4f818491efc67e9373aa16b123c3f522 <48f091fd50b2eb33ae5eaea9ed3c4f81603acf38
  4. Affected versionversion=5.15.162 <5.15.163
  5. Affected versionversion=6.1.96 <6.1.98
  6. Affected versionversion=6.6.36 <6.6.39
  7. Affected versionversion=6.9.7 <6.9.9
  8. Affected versionversion=ab58fe210c40e582a9fd3d122ae21071adb5470a <326fa14549d7969ef80d3f5beea5470cd1c8e67f
  9. Affected versionversion=bf1e8c21f2bef7dfcdadc93b0bb2e8723639d5f7 <f8e960be923f74a273c62478c9cab9523936752b

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=15cb476ceb7da730857b8e94f06161273adb7a3a <aa1d8cc0cc500e06b316cd6732d4e6c1388fe33c; version=2311fd03027d2c1b2ac4a3a41153a16352659b65 <522b39bd7163e8dc49f8cf10b9b782218ac48746; version=4eb4e85c4f818491efc67e9373aa16b123c3f522 <48f091fd50b2eb33ae5eaea9ed3c4f81603acf38; version=5.15.162 <5.15.163; version=6.1.96 <6.1.98; version=6.6.36 <6.6.39; version=6.9.7 <6.9.9; version=ab58fe210c40e582a9fd3d122ae21071adb5470a <326fa14549d7969ef80d3f5beea5470cd1c8e67f; version=bf1e8c21f2bef7dfcdadc93b0bb2e8723639d5f7 <f8e960be923f74a273c62478c9cab9523936752b

Published CVSS scores

5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.8LinuxCVSS: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

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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

T1499.004Endpoint Denial of Service: Application 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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