CVE-2026-90262 btrfs: retry verity reads for not-uptodate Merkle folios
A local attacker can cause persistent I/O errors in btrfs verity operations by triggering transient read failures, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90262?
CVE-2026-90262 is a denial of service vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
btrfs: retry verity reads for not-uptodate Merkle folios
btrfs_read_merkle_tree_page() can find a folio in the mapping that is not uptodate. After taking the folio lock, the current code treats that state as a read error and returns -EIO.
That can make a previous transient read failure sticky. If the failed read left a not-uptodate folio in the mapping, later callers find that folio and fail instead of retrying the read.
Keep the existing page-cache insertion and locking order, but retry the Merkle item read when a not-uptodate folio is found in the mapping. Also unlock the folio when read_key_bytes() fails so that a later caller can lock it and retry the read.
Which versions are affected by CVE-2026-90262?
How do I fix CVE-2026-90262?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-90262 being exploited?
There is no known exploitation of CVE-2026-90262 in the wild and no public exploit code.
Sources
Also known as AZL-102441, BELL-CVE-2026-90262, DEBIAN-CVE-2026-90262, GHSA-hxmf-49q3-qmv4, UBUNTU-CVE-2026-90262.