CVE-2024-44963: Linux kernel · btrfs: do not BUG_ON() when freeing tree block after error
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 6.8.0-1020.22~22.04.1 : update Linux kernel when convenient.
Data as of 28 Oct 2026, 11:13 UTC
- Patch
- Available – fixed in 6.8.0-1020.22~22.04.1, 6.8.0-1020.23~22.04.1, 6.8.0-1019.21~22.04.1 +20
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 4 Sep 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
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-gkeoppkg:deb/ubuntu/linux-gkeop?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.
Description
In the Linux kernel, the following vulnerability has been resolved: btrfs: do not BUG_ON() when freeing tree block after error When freeing a tree block, at btrfs_free_tree_block(), if we fail to create a delayed reference we don't deal with the error and just do a BUG_ON(). The error most likely to happen is -ENOMEM, and we have a comment mentioning that only -ENOMEM can happen, but that is not true, because in case qgroups are enabled any error returned from btrfs_qgroup_trace_extent_post() (can be -EUCLEAN or anything returned from btrfs_search_slot() for example) can be propagated back to btrfs_free_tree_block(). So stop doing a BUG_ON() and return the error to the callers and make them abort the transaction to prevent leaking space. Syzbot was triggering this, likely due to memory allocation failure injection.
References
- ubuntu.com/security/CVE-2024-44963 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2024-44963 (opens in a new tab)
- git.kernel.org/linus/bb3868033a4cccff7be57e9145f2117cbdc91c11 (opens in a new tab)
- git.kernel.org/stable/c/98251cd60b4d702a8a81de442ab621e83a3fb24f (opens in a new tab)
- git.kernel.org/stable/c/bb3868033a4cccff7be57e9145f2117cbdc91c11 (opens in a new tab)
- ubuntu.com/security/notices/USN-7154-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7155-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7156-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7154-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7196-1 (opens in a new tab)