# CVE-2023-29935: Denial of service in n/a

> An assertion failure in LLVM can cause a denial of service when processing specific operations, affecting developers and users of the compiler infrastructure.

- **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:** 5 May 2023
- **Updated:** 29 Jan 2025
- **Also known as:** AZL-26687, AZL-26693, DEBIAN-CVE-2023-29935, GHSA-2wrh-j8p9-w4c5, UBUNTU-CVE-2023-29935

## What is CVE-2023-29935?

CVE-2023-29935 is a medium-severity denial of service vulnerability in n/a, published on 5 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

llvm-project commit a0138390 was discovered to contain an assertion failure at !replacements.count(op) && "operation was already replaced.

Weakness: CWE-617 (Reachable Assertion)

## Which versions are affected by CVE-2023-29935?

It affects 1 product.


Products: Llvm Llvm.

## How do I fix CVE-2023-29935?

Apply the vendor's patch.

## Is CVE-2023-29935 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-29935 exists.

## Other vulnerabilities in n/a

- [CVE-2023-29932](https://insights.sbomify.com/CVE-2023-29932/): Null dereference in n/a (medium 5.5)
- [CVE-2023-29933](https://insights.sbomify.com/CVE-2023-29933/): Null dereference in n/a (medium 5.5)
- [CVE-2023-29934](https://insights.sbomify.com/CVE-2023-29934/): Null dereference in n/a (medium 5.5)
- [CVE-2023-29939](https://insights.sbomify.com/CVE-2023-29939/): Null dereference in n/a (medium 5.5)
- [CVE-2023-29941](https://insights.sbomify.com/CVE-2023-29941/): Null dereference in n/a (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-29935 and fix it if it is affected.

What it is: CVE-2023-29935 is a medium-severity denial of service vulnerability in n/a, published on 5 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-2023-29935 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-2023-29935/ (Markdown: https://insights.sbomify.com/CVE-2023-29935/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-29935
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-29935
- OSV: https://osv.dev/vulnerability/CVE-2023-29935

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-29935/
Summaries are generated and may contain mistakes; the official description above is the record.