# CVE-2020-24241: Use after free in n/a

> A heap use-after-free in NASM allows attackers to execute arbitrary code or cause denial of service via crafted assembly files.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 25 Aug 2020
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-24241, GHSA-x2g3-wj9f-6wcx, UBUNTU-CVE-2020-24241

## What is CVE-2020-24241?

CVE-2020-24241 is a medium-severity use after free vulnerability in Nasm Netwide Assembler, published on 25 Aug 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 Netwide Assembler (NASM) 2.15rc10, there is heap use-after-free in saa_wbytes in nasmlib/saa.c.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2020-24241?

It affects 1 product.


Products: Nasm Netwide Assembler.

## How do I fix CVE-2020-24241?

Upgrade to a fixed version.

## Is CVE-2020-24241 being exploited?

There is no known exploitation of CVE-2020-24241 in the wild and no public exploit code.

## Other vulnerabilities in Nasm Netwide Assembler

- [CVE-2004-1287](https://insights.sbomify.com/CVE-2004-1287/): Memory corruption in n/a (critical 10.0)
- [CVE-2020-24978](https://insights.sbomify.com/CVE-2020-24978/): Use after free in n/a (critical 9.8)
- [CVE-2008-7177](https://insights.sbomify.com/CVE-2008-7177/): Memory corruption in n/a (critical 9.3)
- [CVE-2023-31722](https://insights.sbomify.com/CVE-2023-31722/): Memory corruption in n/a (high 7.8)
- [CVE-2022-44370](https://insights.sbomify.com/CVE-2022-44370/): Memory corruption in n/a (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-24241 and fix it if it is affected.

What it is: CVE-2020-24241 is a medium-severity use after free vulnerability in Nasm Netwide Assembler, published on 25 Aug 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-2020-24241 in the wild and no public exploit code.

Affected product: Nasm Netwide Assembler. 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-2020-24241/ (Markdown: https://insights.sbomify.com/CVE-2020-24241/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-24241
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-24241
- OSV: https://osv.dev/vulnerability/CVE-2020-24241

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-24241/
Summaries are generated and may contain mistakes; the official description above is the record.