# CVE-2021-27562: Arm Trusted Firmware Out-of-Bounds Write

> Attackers in the non-secure world can trigger system halts, overwrite secure data, or leak secure data via secure function calls.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Yes, since 3 Nov 2021 (CISA KEV)
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 25 May 2021
- **Updated:** 21 Oct 2025
- **Also known as:** GHSA-3352-gx8m-f7v5

## What is CVE-2021-27562?

CVE-2021-27562 is a medium-severity memory corruption vulnerability in n/a, published on 25 May 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In Arm Trusted Firmware M through 1.2, the NS world may trigger a system halt, an overwrite of secure data, or the printing out of secure data when calling secure functions under the NSPE handler mode.

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

## Which versions are affected by CVE-2021-27562?

It affects 1 product.


Products: Trustedfirmware Trusted Firmware-M.

## How do I fix CVE-2021-27562?

No fix has been published for CVE-2021-27562 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 17 Nov 2021.

## Is CVE-2021-27562 being exploited?

Yes. Attackers have exploited CVE-2021-27562 in the wild since at least 3 Nov 2021.

## Other vulnerabilities in n/a

- [CVE-2021-43619](https://insights.sbomify.com/CVE-2021-43619/): Memory corruption in n/a (high 7.8)
- [CVE-2023-40271](https://insights.sbomify.com/CVE-2023-40271/): Security feature bypass in n/a (high 7.5)
- [CVE-2021-32032](https://insights.sbomify.com/CVE-2021-32032/): Memory corruption in n/a (high 7.5)
- [CVE-2021-40327](https://insights.sbomify.com/CVE-2021-40327/): Missing authorization in n/a (medium 5.9)
- [CVE-2023-51712](https://insights.sbomify.com/CVE-2023-51712/): Information disclosure in n/a (medium 4.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-27562 and fix it if it is affected.

What it is: CVE-2021-27562 is a medium-severity memory corruption vulnerability in n/a, published on 25 May 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2021-27562 in the wild since at least 3 Nov 2021.

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-2021-27562/ (Markdown: https://insights.sbomify.com/CVE-2021-27562/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27562
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27562
- OSV: https://osv.dev/vulnerability/CVE-2021-27562

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-27562/
Summaries are generated and may contain mistakes; the official description above is the record.