CVE-2026-43046: Linux kernel · btrfs: reject root items with drop_progress and zero drop_level
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 12 Nov 2026, 00:50 UTC
Rated High by Threat Radar's AI analysis · No CVSS score from NVD or the CNA
Thin evidence
One scorer or noneExploitation evidence
Disclosed: evidence found.
CVE published 1 May 2026
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 11 Nov 2026.
What to do
AI-suggested
A fix is available that validates the root_item invariant during disk reads and rejects malformed metadata before it triggers a kernel BUG. Users should update to a Linux kernel version that includes this fix. No additional mitigation is required once the patch is applied.
Description
A vulnerability in the Linux kernel's Btrfs filesystem allows malformed root items with a non-zero drop_progress and zero drop_level to cause a kernel BUG during mount-time relocation recovery. This occurs because the kernel did not validate this invariant when reading root items from disk, allowing corrupted metadata to trigger a BUG_ON condition and crash the kernel. The issue has been fixed by adding validation in the tree-checker to reject such malformed metadata before it causes a crash.
References
- git.kernel.org/stable/c/bedaf7d0b9d793e116f16b4d9a7dbc94bcc80443 (opens in a new tab)
- git.kernel.org/stable/c/ac68a9a8e481ab1becaed29d6d23087dac3de15d (opens in a new tab)
- git.kernel.org/stable/c/295f8075d00442d71dc9ccae421ace1c0d2d9224 (opens in a new tab)
- git.kernel.org/stable/c/53ceedd1eb6280ca8359664e0226983eded2ed73 (opens in a new tab)
- git.kernel.org/stable/c/850de3d87f4720b71ccdcd44f4aa57e46b53a3f3 (opens in a new tab)
- git.kernel.org/stable/c/de585ee18dd5601745f65a60fef7b7ceebd78c83 (opens in a new tab)
- git.kernel.org/stable/c/b17b79ff896305fd74980a5f72afec370ee88ca4 (opens in a new tab)