CVE-2026-68164

What the bug is

damon_set_regions() assumes the input ranges are sorted by the address and don't overlap each other. Hence the assumption was initially to be explicitly validated. But commit 97d482f4592f ("mm/damon/sysfs: reuse damon_set_regions() for regions setting") has mistakenly removed the validation. This can make DAMON behave in unexpected ways. At the best, the monitoring results snapshot will just look weird since there will be overlapping regions. DAMOS will also work weirdly, applying the same action multiple times for overlapping regions, and make DAMOS quota weird. More seriously, depending on the setup and regions updates sequence, negative size regions can be made. It will trigger WARN_ONCE() if the kernel is built with CONFIG_DAMON_DEBUG_SANITY=y. Depending on the monitoring results, the negative size region can further trigger division by zero in damon_merge_two_regions(). Note that some of the consequences including the WARN_ONCE() and the divide by zero depend on commits that were introduced after the root cause commit 97d482f4592f ("mm/damon/sysfs: reuse damon_set_regions() for regions setting"). Fix the problems by checking the assumption and returning an error if the input ranges don't meet the assumption. The issue was discovered [1] by Sashiko.

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.

mm/damon/core.c

What this is

DAMONMAINTAINERS section matched on mm/damon/ · damon@lists.linux.dev · Maintained

Check it on the machine

grep -w CONFIG_DAMON /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.

Show whether Debian builds this, per release

Debian does not build this code in 1 release. It does build it in 4 releases, so the answer depends on which release the machine runs.

• bookwormn
• trixie, forky, sid, bookworm · linux-6.12y

n

not enabled on any flavour - this release does not build the code

y

built into the kernel image on every flavour - only a patch removes it

Build switch

CONFIG_DAMON

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

2026-08-10 (2 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.21%, higher than 11.1% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

mm/damon

Upstream fixes

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

Introduced	Fixed in	Commit
5.19	6.1.183	a5c453fffb6f
5.19	6.6.148	4b4a3e7ef7bb
5.19	6.12.101	06a4beeeec8f
5.19	6.18.42	6ce0db97fb37
5.19	7.1.6	e33adf96afb5
5.19	7.2	954157679ec3

Debian advisories