# CVE-2026-109587: Incorrect authorization in the Arm Cortex-R82 MPU port in FreeRTOS-Kernel

> An unprivileged task can read and write privileged kernel memory via a buffer argument in MPU-enabled builds, requiring an upgrade to fix.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA: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:** No
- **Published:** 16 Oct 2026
- **Updated:** 20 Oct 2026
- **Also known as:** GHSA-pv9j-rq42-3fjc

## What is CVE-2026-109587?

CVE-2026-109587 is a critical missing authorization vulnerability in FreeRTOS-Kernel, published on 16 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Incorrect authorization in the Arm Cortex-R82 (Armv8-R AArch64) MPU port in FreeRTOS-Kernel V11.3.0 and V11.3.1 might allow an unprivileged task on MPU-enabled builds to read and write privileged kernel memory outside the regions assigned to it, via a buffer argument passed to an MPU system call.

To remediate this issue, users should upgrade to version V11.3.2 or later.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2026-109587?


## How do I fix CVE-2026-109587?

No fix has been published for CVE-2026-109587 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-109587 being exploited?

There is no known exploitation of CVE-2026-109587 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-109587 and fix it if it is affected.

What it is: CVE-2026-109587 is a critical missing authorization vulnerability in FreeRTOS-Kernel, published on 16 Oct 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-2026-109587 in the wild and no public exploit code.

Affected product: FreeRTOS-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-2026-109587/ (Markdown: https://insights.sbomify.com/CVE-2026-109587/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-109587
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-109587
- OSV: https://osv.dev/vulnerability/CVE-2026-109587

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-109587/
Summaries are generated and may contain mistakes; the official description above is the record.