# CVE-2026-90271: arm_mpam: Fix a NULL pointer dereference on unbinding after an error interrupt

> A local attacker can cause a kernel crash by unbinding an MSC device after an error interrupt, leading to a denial of service.

- **Severity:** Not scored
- **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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-90271, GHSA-p39c-xj5c-vgmf, UBUNTU-CVE-2026-90271

## What is CVE-2026-90271?

CVE-2026-90271 is a vulnerability in Linux, published on 17 Sep 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:

arm_mpam: Fix a NULL pointer dereference on unbinding after an error interrupt

If a user unbinds an MSC after mpam_disable() has been run in response
to an error interrupt then a dereference of a NULL pointer occurs as
mpam_disable() sets the drvdata to NULL. Add an early return to the driver
remove callback to avoid this.

## Which versions are affected by CVE-2026-90271?


## How do I fix CVE-2026-90271?

Apply the vendor's patch.

## Is CVE-2026-90271 being exploited?

There is no known exploitation of CVE-2026-90271 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90271 and fix it if it is affected.

What it is: CVE-2026-90271 is a vulnerability in Linux, published on 17 Sep 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-2026-90271 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-2026-90271/ (Markdown: https://insights.sbomify.com/CVE-2026-90271/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90271
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90271
- OSV: https://osv.dev/vulnerability/CVE-2026-90271

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90271/
Summaries are generated and may contain mistakes; the official description above is the record.