CVE-2024-49868

Kernel crash via unchecked btrfs relocation control

Published Oct 21, 2024 · Updated May 11, 2026

NULL pointer dereference in the Linux btrfs relocation code allows local users to crash the kernel during a filesystem balance. After start_transaction fails in prepare_to_relocate, cleanup clears fs_info->reloc_ctl, but btrfs_update_reloc_root dereferences it during the final commit without first checking for NULL. The crash requires local low-privileged access, an allocation failure during relocation, and a concurrent subvolume update that creates a relocation root.

CVSS severity5.5
Medium
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in the Linux btrfs relocation code allows local users to crash the kernel during a filesystem balance. After start_transaction fails in prepare_to_relocate, cleanup clears fs_info->reloc_ctl, but btrfs_update_reloc_root dereferences it during the final commit without first checking for NULL. The crash requires local low-privileged access, an allocation failure during relocation, and a concurrent subvolume update that creates a relocation root.

The record

CVE
CVE-2024-49868
Published
Oct 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 21, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=2.6.35
  2. Affected versionversion=3fd0a5585eb98e074fb9934549c8d85c49756c0d <1282f001cbf56e5dd6e90a18e205a566793f4be0
  3. Affected versionversion=3fd0a5585eb98e074fb9934549c8d85c49756c0d <37fee9c220b92c3b7bf22b51c51dde5364e7590b
  4. Affected versionversion=3fd0a5585eb98e074fb9934549c8d85c49756c0d <39356ec0e319ed07627b3a0f402d0608546509e6
  5. Affected versionversion=3fd0a5585eb98e074fb9934549c8d85c49756c0d <7ad0c5868f2f0418619089513d95230c66cb7eb4
  6. Affected versionversion=3fd0a5585eb98e074fb9934549c8d85c49756c0d <c3b47f49e83197e8dffd023ec568403bcdbb774b
  7. Affected versionversion=3fd0a5585eb98e074fb9934549c8d85c49756c0d <d13249c0df7aab885acb149695f82c54c0822a70
  8. Affected versionversion=3fd0a5585eb98e074fb9934549c8d85c49756c0d <d73d48acf36f57362df7e4f9d76568168bf5e944
  9. Affected versionversion=3fd0a5585eb98e074fb9934549c8d85c49756c0d <dc02c1440705e3451abd1c2c8114a5c1bb188e9f

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.35; version=3fd0a5585eb98e074fb9934549c8d85c49756c0d <1282f001cbf56e5dd6e90a18e205a566793f4be0; version=3fd0a5585eb98e074fb9934549c8d85c49756c0d <37fee9c220b92c3b7bf22b51c51dde5364e7590b; version=3fd0a5585eb98e074fb9934549c8d85c49756c0d <39356ec0e319ed07627b3a0f402d0608546509e6; version=3fd0a5585eb98e074fb9934549c8d85c49756c0d <7ad0c5868f2f0418619089513d95230c66cb7eb4; version=3fd0a5585eb98e074fb9934549c8d85c49756c0d <c3b47f49e83197e8dffd023ec568403bcdbb774b; version=3fd0a5585eb98e074fb9934549c8d85c49756c0d <d13249c0df7aab885acb149695f82c54c0822a70; version=3fd0a5585eb98e074fb9934549c8d85c49756c0d <d73d48acf36f57362df7e4f9d76568168bf5e944; version=3fd0a5585eb98e074fb9934549c8d85c49756c0d <dc02c1440705e3451abd1c2c8114a5c1bb188e9f

Published CVSS scores

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

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-476NULL Pointer Dereference
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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