# CVE-2020-5213: NetHack SYMBOL configuration file option is subject to a buffer overflow

> Attackers can trigger a buffer overflow via long SYMBOL config values in suid/sgid NetHack installations, leading to code execution or privilege escalation.

- **Severity:** Medium 5.0 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 28 Jan 2020
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-5213, GHSA-rr25-4v34-pr7v, UBUNTU-CVE-2020-5213

## What is CVE-2020-5213?

CVE-2020-5213 is a medium-severity memory corruption vulnerability in NetHack, published on 28 Jan 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

In NetHack before 3.6.5, too long of a value for the SYMBOL configuration file option can cause a buffer overflow resulting in a crash or remote code execution/privilege escalation. This vulnerability affects systems that have NetHack installed suid/sgid and shared systems that allow users to upload their own configuration files. Users should upgrade to NetHack 3.6.5.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2020-5213?

It affects 1 product.


Products: Nethack Nethack.

## How do I fix CVE-2020-5213?

Upgrade to a fixed version.

## Is CVE-2020-5213 being exploited?

There is no known exploitation of CVE-2020-5213 in the wild and no public exploit code.

## Other vulnerabilities in NetHack

- [CVE-2019-19905](https://insights.sbomify.com/CVE-2019-19905/): Memory corruption in n/a (critical 9.8)
- [CVE-2023-24809](https://insights.sbomify.com/CVE-2023-24809/): NetHack Call command buffer overflow (medium 5.5)
- [CVE-2020-5209](https://insights.sbomify.com/CVE-2020-5209/): NetHack command line parsing of options starting with -de and -i is subject to a buffer overflow (medium 5.0)
- [CVE-2020-5210](https://insights.sbomify.com/CVE-2020-5210/): NetHack command line -w option parsing is subject to a buffer overflow (medium 5.0)
- [CVE-2020-5211](https://insights.sbomify.com/CVE-2020-5211/): NetHack AUTOCOMPLETE configuration file option is subject to a buffer overflow (medium 5.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-5213 and fix it if it is affected.

What it is: CVE-2020-5213 is a medium-severity memory corruption vulnerability in NetHack, published on 28 Jan 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-5213 in the wild and no public exploit code.

Affected product: NetHack. 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-2020-5213/ (Markdown: https://insights.sbomify.com/CVE-2020-5213/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-5213
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-5213
- OSV: https://osv.dev/vulnerability/CVE-2020-5213

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-5213/
Summaries are generated and may contain mistakes; the official description above is the record.