# 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.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** BELL-CVE-2026-68164, DEBIAN-CVE-2026-68164, GHSA-9xf8-5fr7-rcpw, UBUNTU-CVE-2026-68164

## 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.

## Is CVE-2026-68164 being exploited?

There is no known exploitation of CVE-2026-68164 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68164 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-68164 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-68164/ (Markdown: https://insights.sbomify.com/CVE-2026-68164/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68164
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68164
- OSV: https://osv.dev/vulnerability/CVE-2026-68164

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68164/
Summaries are generated and may contain mistakes; the official description above is the record.