# OSV-2024-319: Stack-buffer-underflow in filter_apply_chain

> A stack-buffer-underflow in filter_apply_chain can cause crashes or potential code execution in affected libraries.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not stated
- **Attackable:** Not stated
- **Victim action needed:** Not stated
- **Fix available:** No
- **Published:** 29 Apr 2024

## What is OSV-2024-319?

OSV-2024-319 is a memory corruption vulnerability in flex, published on 29 Apr 2024. 

### Official description

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=68328

```
Crash type: Stack-buffer-underflow READ 4
Crash state:
filter_apply_chain
filter_apply_chain
initialize_output_filters
```

## Which versions are affected by OSV-2024-319?

1 open source package ship an affected version, including flex.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `flex` | OSS-Fuzz | All versions | None |

## How do I fix OSV-2024-319?

No fix has been published for OSV-2024-319 yet. Limit exposure of the affected software until one is available.

## Is OSV-2024-319 being exploited?

There is no known exploitation of OSV-2024-319 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for OSV-2024-319 and fix it if it is affected.

What it is: OSV-2024-319 is a memory corruption vulnerability in flex, published on 29 Apr 2024. 
Exploitation: There is no known exploitation of OSV-2024-319 in the wild and no public exploit code.

Affected packages and fixed versions:
- flex (OSS-Fuzz): affected all versions; no fix listed

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/OSV-2024-319/ (Markdown: https://insights.sbomify.com/OSV-2024-319/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/OSV-2024-319

---
From sbomify Insights: https://insights.sbomify.com/OSV-2024-319/
Summaries are generated and may contain mistakes; the official description above is the record.