CVE-2026-68164 mm/damon/core: disallow overlapping input ranges for damon_set_regions()
A missing validation in the Linux kernel DAMON subsystem allows local privileged users to trigger a division by zero, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-68164?
CVE-2026-68164 is a denial of service vulnerability in Linux, published on 10 Aug 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:
mm/damon/core: disallow overlapping input ranges for damon_set_regions()
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.
Which versions are affected by CVE-2026-68164?
How do I fix CVE-2026-68164?
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-2026-68164 being exploited?
There is no known exploitation of CVE-2026-68164 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-68164, DEBIAN-CVE-2026-68164, GHSA-9xf8-5fr7-rcpw, UBUNTU-CVE-2026-68164.