# CVE-2026-77236: Missing size validation in SecureContext_AllocateContext in FreeRTOS-Kernel

> Local attackers can corrupt secure-world heap metadata via out-of-bounds write in FreeRTOS-Kernel, potentially leading to code execution or privilege escalation.

- **Severity:** High 8.3 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:H/SC:N/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:** 21 Aug 2026

## What is CVE-2026-77236?

CVE-2026-77236 is a high-severity memory corruption 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

Missing minimum size validation in secure context allocation in FreeRTOS-Kernel before 11.3.1 might allow local users to corrupt secure-world heap metadata via an out-of-bounds write with an undersized stack size parameter. To remediate this issue, users should upgrade to version 11.3.1 or later.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-77236?

It affects 1 product.


Products: Amazon Freertos.

## How do I fix CVE-2026-77236?

No fix has been published for CVE-2026-77236 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-77236 being exploited?

There is no known exploitation of CVE-2026-77236 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-2026-77234](https://insights.sbomify.com/CVE-2026-77234/): Improper input validation in FreeRTOS-Kernel timer command handling (critical 9.3)
- [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)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-77236 and fix it if it is affected.

What it is: CVE-2026-77236 is a high-severity memory corruption 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-2026-77236 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-2026-77236/ (Markdown: https://insights.sbomify.com/CVE-2026-77236/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-77236
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-77236
- OSV: https://osv.dev/vulnerability/CVE-2026-77236

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-77236/
Summaries are generated and may contain mistakes; the official description above is the record.