CVE-2026-90333

What the bug is

The discard-block check in dm_integrity_rw_tag() treats a stored tag of all 0xf6 bytes (DISCARD_FILLER) as proof a block was discarded and skips HMAC verification. allow_discards is only accepted in dm-integrity's standalone mode. An attacker with raw write access to the backing device, but without the integrity key, can stamp any block with an all-0xf6 tag and have it served as authentic. Add a new "allow_discards_keyed" target argument that marks discarded blocks with a keyed checksum of (salt || sector) instead, computed by integrity_discard_checksum().

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.

Documentation/admin-guide/device-mapper/dm-ima.rst
Documentation/admin-guide/device-mapper/dm-integrity.rst
drivers/md/dm-integrity.c

What this is

DEVICE-MAPPER (LVM)MAINTAINERS section matched on Documentation/admin-guide/device-mapper/ · dm-devel@lists.linux.dev · Maintained

Kernel module

dm_integrity

Check it on the machine

grep -wE 'CONFIG_DM_INTEGRITY|CONFIG_MD' /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 dm_integrity

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, sidm

m

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

Build switches

CONFIG_DM_INTEGRITY, CONFIG_MD

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

0.17%, higher than 5.5% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

Documentation/admin-guide

Upstream fixes

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

Introduced	Fixed in	Commit
5.7	6.18.52	5c58ea19a909
5.7	7.2.6	6228722c2730
5.7	7.3	68c5c42567bc