# CVE-2026-77234: Improper input validation in FreeRTOS-Kernel timer command handling

> An unprivileged task can execute code in privileged kernel context on MPU-enabled FreeRTOS ports due to improper input validation.

- **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:** 21 Aug 2026
- **Updated:** 27 Aug 2026

## What is CVE-2026-77234?

CVE-2026-77234 is a critical vulnerability in FreeRTOS-Kernel, published on 21 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Improper input validation in FreeRTOS-Kernel before 11.3.1 might allow an unprivileged task on MPU-enabled ports to execute code in privileged kernel context. To remediate this issue, users should upgrade to version 11.3.1 or later.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2026-77234?

It affects 1 product.


Products: Amazon Freertos.

## How do I fix CVE-2026-77234?

No fix has been published for CVE-2026-77234 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-77234 being exploited?

There is no known exploitation of CVE-2026-77234 in the wild and no public exploit code.

## Other vulnerabilities in FreeRTOS-Kernel

- [CVE-2021-32020](https://insights.sbomify.com/CVE-2021-32020/): Memory corruption in n/a (critical 9.8)
- [CVE-2021-31571](https://insights.sbomify.com/CVE-2021-31571/): Integer overflow in n/a (critical 9.8)
- [CVE-2021-31572](https://insights.sbomify.com/CVE-2021-31572/): Integer overflow in n/a (critical 9.8)
- [CVE-2024-28115](https://insights.sbomify.com/CVE-2024-28115/): Privilege Escalation in FreeRTOS Kernel ARMv7-M MPU ports and ARMv8-M ports with MPU support enabled (high 8.8)
- [CVE-2026-77235](https://insights.sbomify.com/CVE-2026-77235/): Missing privilege check in SecureContext_FreeContext in FreeRTOS-Kernel (high 8.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-77234 and fix it if it is affected.

What it is: CVE-2026-77234 is a critical vulnerability in FreeRTOS-Kernel, published on 21 Aug 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-2026-77234 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-2026-77234/ (Markdown: https://insights.sbomify.com/CVE-2026-77234/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-77234
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-77234
- OSV: https://osv.dev/vulnerability/CVE-2026-77234

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-77234/
Summaries are generated and may contain mistakes; the official description above is the record.