# CVE-2021-43997: Privilege escalation in n/a

> Attackers with code execution can escalate privileges in FreeRTOS by bypassing MPU protections in ARMv7-M and ARMv8-M ports.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** No
- **Published:** 17 Nov 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-cp2g-q9qc-pm45

## What is CVE-2021-43997?

CVE-2021-43997 is a high-severity vulnerability in n/a, published on 17 Nov 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

FreeRTOS versions 10.2.0 through 10.4.5 do not prevent non-kernel code from calling the xPortRaisePrivilege internal function to raise privilege. FreeRTOS versions through 10.4.6 do not prevent a third party that has already independently gained the ability to execute injected code to achieve further privilege escalation by branching directly inside a FreeRTOS MPU API wrapper function with a manually crafted stack frame. These issues affect ARMv7-M MPU ports, and ARMv8-M ports with MPU support enabled (i.e. configENABLE_MPU set to 1). These are fixed in V10.5.0 and in V10.4.3-LTS Patch 3.

## Which versions are affected by CVE-2021-43997?

It affects 1 product.


Products: Amazon Freertos.

## How do I fix CVE-2021-43997?

No fix has been published for CVE-2021-43997 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-43997 being exploited?

There is no known exploitation of CVE-2021-43997 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [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-2021-43997 and fix it if it is affected.

What it is: CVE-2021-43997 is a high-severity vulnerability in n/a, published on 17 Nov 2021. 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-2021-43997 in the wild and no public exploit code.

Affected product: n/a. 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-2021-43997/ (Markdown: https://insights.sbomify.com/CVE-2021-43997/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-43997
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-43997
- OSV: https://osv.dev/vulnerability/CVE-2021-43997

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-43997/
Summaries are generated and may contain mistakes; the official description above is the record.