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
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
- 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:NExploitation evidence
Disclosed: evidence found.
CVE published 25 Jun 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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.
Patches and advisories
- ubuntu.com/security/notices/USN-6951-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6953-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6951-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6951-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6951-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-6979-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6999-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7004-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7005-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7007-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7008-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7005-2 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-ibmpkg:deb/ubuntu/linux-ibm?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
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
- ubuntu.com/security/CVE-2024-39276 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2024-39276 (opens in a new tab)
- git.kernel.org/linus/0c0b4a49d3e7f49690a6827a41faeffad5df7e21 (opens in a new tab)
- git.kernel.org/stable/c/9ad75e78747b5a50dc5a52f0f8e92e920a653f16 (opens in a new tab)
- git.kernel.org/stable/c/896a7e7d0d555ad8b2b46af0c2fa7de7467f9483 (opens in a new tab)
- git.kernel.org/stable/c/76dc776153a47372719d664e0fc50d6355791abb (opens in a new tab)
- git.kernel.org/stable/c/681ff9a09accd8a4379f8bd30b7a1641ee19bb3e (opens in a new tab)
- git.kernel.org/stable/c/e941b712e758f615d311946bf98216e79145ccd9 (opens in a new tab)
- git.kernel.org/stable/c/a95df6f04f2c37291adf26a74205cde0314d4577 (opens in a new tab)
- git.kernel.org/stable/c/b37c0edef4e66fb21a2fbc211471195a383e5ab8 (opens in a new tab)
- git.kernel.org/stable/c/0c0b4a49d3e7f49690a6827a41faeffad5df7e21 (opens in a new tab)
- ubuntu.com/security/notices/USN-6951-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6953-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6951-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6951-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6951-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-6979-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6999-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7004-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7005-1 (opens in a new tab)