# CVE-2026-31652: mm/damon/stat: deallocate damon_call() failure leaking damon_ctx

> A memory leak in the Linux kernel DAMON subsystem can lead to a use-after-free condition, potentially allowing local attackers to execute arbitrary code or escalate privileges.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Apr 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2026-31652, DEBIAN-CVE-2026-31652, GHSA-jp52-g472-3cpx, UBUNTU-CVE-2026-31652

## What is CVE-2026-31652?

CVE-2026-31652 is a high-severity use after free vulnerability in Linux kernel, published on 24 Apr 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/stat: deallocate damon_call() failure leaking damon_ctx

damon_stat_start() always allocates the module's damon_ctx object
(damon_stat_context).  Meanwhile, if damon_call() in the function fails,
the damon_ctx object is not deallocated.  Hence, if the damon_call() is
failed, and the user writes Y to “enabled” again, the previously
allocated damon_ctx object is leaked.

This cannot simply be fixed by deallocating the damon_ctx object when
damon_call() fails.  That's because damon_call() failure doesn't guarantee
the kdamond main function, which accesses the damon_ctx object, is
completely finished.  In other words, if damon_stat_start() deallocates
the damon_ctx object after damon_call() failure, the not-yet-terminated
kdamond could access the freed memory (use-after-free).

Fix the leak while avoiding the use-after-free by keeping returning
damon_stat_start() without deallocating the damon_ctx object after
damon_call() failure, but deallocating it when the function is invoked
again and the kdamond is completely terminated.  If the kdamond is not yet
terminated, simply return -EAGAIN, as the kdamond will soon be terminated.

The issue was discovered [1] by sashiko.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-31652?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31652?

Apply the vendor's patch.

## Is CVE-2026-31652 being exploited?

There is no known exploitation of CVE-2026-31652 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-31652 and fix it if it is affected.

What it is: CVE-2026-31652 is a high-severity use after free vulnerability in Linux kernel, published on 24 Apr 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-2026-31652 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-31652/ (Markdown: https://insights.sbomify.com/CVE-2026-31652/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31652
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31652
- OSV: https://osv.dev/vulnerability/CVE-2026-31652

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31652/
Summaries are generated and may contain mistakes; the official description above is the record.