# CVE-2021-40040: Memory corruption in HarmonyOS;EMUI;Magic UI

> Attackers can write data to arbitrary memory addresses in the HW_KEYMASTER module, potentially compromising confidentiality on Huawei devices.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Aug 2022
- **Updated:** 6 Mar 2026
- **Also known as:** GHSA-86g3-53hw-mw23

## What is CVE-2021-40040?

CVE-2021-40040 is a high-severity memory corruption vulnerability in Huawei Emui, published on 9 Aug 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Vulnerability of writing data to an arbitrary address in the HW_KEYMASTER module. Successful exploitation of this vulnerability may affect confidentiality.

## Which versions are affected by CVE-2021-40040?

It affects 3 products.


Products: Huawei Emui, Huawei Harmonyos, Huawei Magic Ui.

## How do I fix CVE-2021-40040?

No fix has been published for CVE-2021-40040 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-40040 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-40040 exists.

## Other vulnerabilities in Huawei Emui

- [CVE-2023-52370](https://insights.sbomify.com/CVE-2023-52370/): Memory corruption in EMUI (critical 9.8)
- [CVE-2023-52378](https://insights.sbomify.com/CVE-2023-52378/): Business logic in EMUI (critical 9.8)
- [CVE-2023-52381](https://insights.sbomify.com/CVE-2023-52381/): Code injection in EMUI (critical 9.8)
- [CVE-2023-52103](https://insights.sbomify.com/CVE-2023-52103/): Memory corruption in EMUI (critical 9.8)
- [CVE-2023-46773](https://insights.sbomify.com/CVE-2023-46773/): Privilege escalation in EMUI (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-40040 and fix it if it is affected.

What it is: CVE-2021-40040 is a high-severity memory corruption vulnerability in Huawei Emui, published on 9 Aug 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-40040 exists.

Affected product: Huawei Emui. 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-2021-40040/ (Markdown: https://insights.sbomify.com/CVE-2021-40040/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-40040
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-40040
- OSV: https://osv.dev/vulnerability/CVE-2021-40040

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-40040/
Summaries are generated and may contain mistakes; the official description above is the record.