# CVE-2024-36891: maple_tree: fix mas_empty_area_rev() null pointer dereference

> A local attacker can cause a kernel oops and denial of service by unmapping all VMAs and mapping a new one, triggering a null pointer dereference in the maple tree implementation.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 30 May 2024
- **Updated:** 11 May 2026
- **Also known as:** AZL-42474, BELL-CVE-2024-36891, DEBIAN-CVE-2024-36891, UBUNTU-CVE-2024-36891

## What is CVE-2024-36891?

CVE-2024-36891 is a medium-severity vulnerability in Linux kernel, published on 30 May 2024. 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:

maple_tree: fix mas_empty_area_rev() null pointer dereference

Currently the code calls mas_start() followed by mas_data_end() if the
maple state is MA_START, but mas_start() may return with the maple state
node == NULL.  This will lead to a null pointer dereference when checking
information in the NULL node, which is done in mas_data_end().

Avoid setting the offset if there is no node by waiting until after the
maple state is checked for an empty or single entry state.

A user could trigger the events to cause a kernel oops by unmapping all
vmas to produce an empty maple tree, then mapping a vma that would cause
the scenario described above.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2024-36891?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-36891?

Apply the vendor's patch.

## Is CVE-2024-36891 being exploited?

There is no known exploitation of CVE-2024-36891 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-2024-36891 and fix it if it is affected.

What it is: CVE-2024-36891 is a medium-severity vulnerability in Linux kernel, published on 30 May 2024. 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-2024-36891 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-2024-36891/ (Markdown: https://insights.sbomify.com/CVE-2024-36891/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-36891
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-36891
- OSV: https://osv.dev/vulnerability/CVE-2024-36891

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-36891/
Summaries are generated and may contain mistakes; the official description above is the record.