# CVE-2023-31974: Use after free in n/a

> A use-after-free flaw in the YASM assembler's preprocessor could allow attackers to execute arbitrary code or cause a denial of service.

- **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:** No
- **Published:** 9 May 2023
- **Updated:** 28 Jan 2025
- **Also known as:** AZL-26635, AZL-35382, DEBIAN-CVE-2023-31974, GHSA-57f5-g442-hrw2

## What is CVE-2023-31974?

CVE-2023-31974 is a medium-severity use after free vulnerability in n/a, published on 9 May 2023. 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

yasm v1.3.0 was discovered to contain a use after free via the function error at /nasm/nasm-pp.c. Note: Multiple third parties dispute this as a bug and not a vulnerability according to the YASM security policy.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2023-31974?

It affects 1 product.


Products: Tortall Yasm.

## How do I fix CVE-2023-31974?

No fix has been published for CVE-2023-31974 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-31974 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-31974 exists.

## Other vulnerabilities in n/a

- [CVE-2023-31973](https://insights.sbomify.com/CVE-2023-31973/): Use after free in n/a (high 7.8)
- [CVE-2023-51258](https://insights.sbomify.com/CVE-2023-51258/): Denial of service in n/a (medium 5.5)
- [CVE-2023-31972](https://insights.sbomify.com/CVE-2023-31972/): Use after free in n/a (medium 5.5)
- [CVE-2021-33454](https://insights.sbomify.com/CVE-2021-33454/): Null dereference in n/a (medium 5.5)
- [CVE-2021-33455](https://insights.sbomify.com/CVE-2021-33455/): Null dereference in n/a (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-31974 and fix it if it is affected.

What it is: CVE-2023-31974 is a medium-severity use after free vulnerability in n/a, published on 9 May 2023. 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-31974 exists.

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-2023-31974/ (Markdown: https://insights.sbomify.com/CVE-2023-31974/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-31974
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-31974
- OSV: https://osv.dev/vulnerability/CVE-2023-31974

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-31974/
Summaries are generated and may contain mistakes; the official description above is the record.