# CVE-2020-37221: Atomic Alarm Clock 6.3 Stack Overflow via SEH Unicode

> Local attackers can execute arbitrary code via a stack overflow in the Time Zones Clock configuration display name field.

- **Severity:** High 8.6 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 May 2026
- **Updated:** 13 May 2026
- **Also known as:** GHSA-q8c2-hv55-wmr4

## What is CVE-2020-37221?

CVE-2020-37221 is a high-severity memory corruption vulnerability in Drive-software Atomic Alarm Clock, published on 13 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Atomic Alarm Clock 6.3 contains a stack overflow vulnerability that allows local attackers to execute arbitrary code by supplying a malicious string to the display name textbox in the Time Zones Clock configuration. Attackers can craft a buffer with structured exception handling overwrite and encoded shellcode to bypass SafeSEH protections and execute arbitrary commands with application privileges.

Weakness: CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2020-37221?


## How do I fix CVE-2020-37221?

No fix has been published for CVE-2020-37221 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-37221 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-37221 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-37221 and fix it if it is affected.

What it is: CVE-2020-37221 is a high-severity memory corruption vulnerability in Drive-software Atomic Alarm Clock, published on 13 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-37221 exists.

Affected product: Drive-software Atomic Alarm Clock. 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-2020-37221/ (Markdown: https://insights.sbomify.com/CVE-2020-37221/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-37221
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-37221
- OSV: https://osv.dev/vulnerability/CVE-2020-37221

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-37221/
Summaries are generated and may contain mistakes; the official description above is the record.