# OSV-2022-327: Stack-use-after-return in QSemaphore::release

> A stack-use-after-return vulnerability in Qt's QSemaphore allows attackers to potentially execute arbitrary code or cause a denial of service via crafted input.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Not stated
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Apr 2022

## What is OSV-2022-327?

OSV-2022-327 is an use after free vulnerability in qt, published on 10 Apr 2022. 

### Official description

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=46525

The issue already existed before oss-fuzz could reproduce it. oss-fuzz found
it after qdrawhelper routines were made multithreaded. There might be ways to
trigger the issue before that.

```
Crash type: Stack-use-after-return WRITE 8
Crash state:
QSemaphore::release
std::__1::__function::__func<void handleSpans<BlendSrcGeneric>
FunctionRunnable::run
```

## Which versions are affected by OSV-2022-327?

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


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

## How do I fix OSV-2022-327?

No fix has been published for OSV-2022-327 yet. Limit exposure of the affected software until one is available.

## Is OSV-2022-327 being exploited?

There is no known exploitation of OSV-2022-327 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for OSV-2022-327 and fix it if it is affected.

What it is: OSV-2022-327 is an use after free vulnerability in qt, published on 10 Apr 2022. 
Exploitation: There is no known exploitation of OSV-2022-327 in the wild and no public exploit code.

Affected packages and fixed versions:
- qt (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-2022-327/ (Markdown: https://insights.sbomify.com/OSV-2022-327/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/OSV-2022-327

---
From sbomify Insights: https://insights.sbomify.com/OSV-2022-327/
Summaries are generated and may contain mistakes; the official description above is the record.