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VulnerabilityPublished Updated

CVE-2024-39276: Linux kernel · ext4: fix mb_cache_entry's e_refcnt leak in ext4_xattr_block_cache_find()

Affects Linux kernelSource GCVE Database

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Not known to be exploited · CVSS 5.5 Medium · fixed in 5.4.0-1130.140~18.04.1 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 15:18 UTC

CVSS 3.1 base score
5.5Medium
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 5.4.0-1130.140~18.04.1, 5.4.0-1135.142~18.04.1, 5.4.0-1134.143~18.04.1 +71
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Jun 2024

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-44.44
Fixed in
  • 6.8.0-44.44
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1015.16
Fixed in
  • 6.8.0-1015.16
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1014.16
Fixed in
  • 6.8.0-1014.16
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1014.16
Fixed in
  • 6.8.0-1014.16
Ubuntu 24.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1010.13
Fixed in
  • 6.8.0-1010.13
Ubuntu 24.04 LTSlinux-ibmpkg:deb/ubuntu/linux-ibm?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1012.12
Fixed in
  • 6.8.0-1012.12

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and has been released in multiple Linux kernel versions, including 5.4.0-1130.140~18.04.1 and later. Users should update their Linux kernel to a fixed version as listed in the established facts. After updating, a system reboot is required to apply the fix. Due to an ABI change, third-party kernel modules may need recompilation and reinstallation. No additional mitigation actions are required beyond applying the official kernel update.

Description

CVE-2024-39276 is a vulnerability in the Linux kernel's ext4 filesystem implementation involving a reference count leak in the mb_cache_entry structure within ext4_xattr_block_cache_find(). This occurs when ext4_sb_bread() returns an -ENOMEM error, causing the reference count to leak and eventually trigger a warning in mb_cache_destroy(). The issue has been fixed in multiple Linux kernel versions. The vulnerability has a medium severity with a CVSS score of 5.5 and does not have known exploits in the wild.

References

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