CVE-2026-90262

What the bug is

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.

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

fs/btrfs/verity.c

What this is

BTRFS FILE SYSTEMMAINTAINERS section matched on fs/btrfs/ · linux-btrfs@vger.kernel.org · Maintained

Kernel module

btrfs

Check it on the machine

grep -wE 'CONFIG_BTRFS_FS|CONFIG_FS_VERITY' /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

lsmod | grep -w btrfs

Prints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.

Show whether Debian builds this, per release

Debian builds this as a loadable module. Every release below compiles it as a module on every flavour, so whether the code is in the running kernel depends on whether that module is loaded.

• bookworm, trixie, forky, sid, bookworm · linux-6.12m

m

a loadable module on every flavour - check lsmod, can be blacklisted

Build switches

CONFIG_BTRFS_FS, CONFIG_FS_VERITY

Reads as

all on means the file is compiled; any one off means it is not.

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2026-09-17 (31 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.20%, higher than 9.2% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

unimportantsource

Subsystem

fs/btrfs

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
6.6	6.6.157	90e9eae1b590
6.6	6.12.110	c1fa005cdf3b
6.6	6.18.52	12b6d1a1715c
6.6	7.2.6	81241f734f0f
6.6	7.3	8cc569696dac

Debian advisories