# CVE-2026-99036: dm: fix reading free memory in do_resume


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 23 Oct 2026
- **Updated:** 26 Oct 2026
- **Also known as:** AZL-110903, BELL-CVE-2026-99036, DEBIAN-CVE-2026-99036, GHSA-4cj3-mpcr-rfqf, UBUNTU-CVE-2026-99036

## What is CVE-2026-99036?

CVE-2026-99036 is a vulnerability in Linux, published on 23 Oct 2026. 

### Official description

In the Linux kernel, the following vulnerability has been resolved:

dm: fix reading free memory in do_resume

When do_resume calls dm_table_get_mode(new_map), the call is done without
holding any locks (it only holds a reference to the md). It may be
possible that another concurrent ioctl on the same device will swap table
after dm_swap_table and before dm_table_get_mode. In this case,
dm_table_get_mode(new_map) reads freed memory.

This race condition was triggered by syzbot.

This commit fixes the race by reading mode of the new table before
dm_swap_table. Note that new_map is also passed to dm_ima_need_measure,
but this function doesn't attempt to dereference it, so this call should
be safe.

Note that this is not a security bug because only root can trigger it and
the commonly used tools such as lvm or cryptsetup do not call the ioctls
concurrently, so that they can't trigger it acceidentally.

## Which versions are affected by CVE-2026-99036?


## How do I fix CVE-2026-99036?

Upgrade to a fixed version.

## Is CVE-2026-99036 being exploited?

There is no known exploitation of CVE-2026-99036 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-99036 and fix it if it is affected.

What it is: CVE-2026-99036 is a vulnerability in Linux, published on 23 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-99036 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-2026-99036/ (Markdown: https://insights.sbomify.com/CVE-2026-99036/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-99036
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-99036
- OSV: https://osv.dev/vulnerability/CVE-2026-99036

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-99036/
Summaries are generated and may contain mistakes; the official description above is the record.