CVE-2024-56581: Linux kernel · btrfs: ref-verify: fix use-after-free after invalid ref action
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 4.15.0-1197.212~14.04.1 : patch Linux kernel soon.
Data as of 12 Nov 2026, 19:11 UTC
- Patch
- Available – fixed in 4.15.0-1197.212~14.04.1, 4.15.0-1189.202~16.04.1, 4.15.0-1197.212~16.04.1 +99
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 27 Dec 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 12 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-7379-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7380-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7381-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7382-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7387-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7388-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7389-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7390-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7387-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7387-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7391-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7392-1 (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-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia?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
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch addressing this vulnerability is available and included in updated Linux kernel releases such as 4.15.0-1197.212~14.04.1 and later versions listed in the established facts. Users and administrators should apply these official kernel updates promptly to remediate the issue. No additional mitigation steps are indicated by the vendor advisory.
Description
CVE-2024-56581 is a use-after-free vulnerability in the Btrfs filesystem implementation of the Linux kernel. It occurs in the btrfs_ref_tree_mod() function when an invalid ref action (BTRFS_DROP_DELAYED_REF) triggers freeing a reference entry without properly removing it from the red-black tree, leading to a use-after-free condition. This flaw has been fixed by ensuring the ref entry is removed from the tree before being freed. The vulnerability affects multiple Linux kernel versions, particularly those before certain 4.15.x releases and some 4.11.x and 4.13.x versions. A patch is available and included in updated kernel releases.
References
- ubuntu.com/security/CVE-2024-56581 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2024-56581 (opens in a new tab)
- git.kernel.org/linus/7c4e39f9d2af4abaf82ca0e315d1fd340456620f (opens in a new tab)
- git.kernel.org/stable/c/4275ac2741941c9c7c2293619fdbacb9f70ba85b (opens in a new tab)
- git.kernel.org/stable/c/6370db28af9a8ae3bbdfe97f8a48f8f995e144cf (opens in a new tab)
- git.kernel.org/stable/c/6fd018aa168e472ce35be32296d109db6adb87ea (opens in a new tab)
- git.kernel.org/stable/c/7c4e39f9d2af4abaf82ca0e315d1fd340456620f (opens in a new tab)
- git.kernel.org/stable/c/a6f9e7a0bf1185c9070c0de03bb85eafb9abd650 (opens in a new tab)
- git.kernel.org/stable/c/d2b85ce0561fde894e28fa01bd5d32820d585006 (opens in a new tab)
- git.kernel.org/stable/c/dfb9fe7de61f34cc241ab3900bdde93341096e0e (opens in a new tab)
- ubuntu.com/security/notices/USN-7379-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7380-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7381-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7382-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7387-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7388-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7389-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7390-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7387-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7387-3 (opens in a new tab)