# OSV-2020-1521: Use-of-uninitialized-value in stbi__jpeg_huff_decode

> An attacker can cause a denial of service via a crafted JPEG image due to use of uninitialized values in the stb image library.

- **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:** 28 Jul 2020

## What is OSV-2020-1521?

OSV-2020-1521 is a vulnerability in stb, published on 28 Jul 2020. 

### Official description

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=22598

```
Crash type: Use-of-uninitialized-value
Crash state:
stbi__jpeg_huff_decode
stbi__jpeg_decode_block_prog_ac
stbi__parse_entropy_coded_data
```

## Which versions are affected by OSV-2020-1521?

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


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

## How do I fix OSV-2020-1521?

No fix has been published for OSV-2020-1521 yet. Limit exposure of the affected software until one is available.

## Is OSV-2020-1521 being exploited?

There is no known exploitation of OSV-2020-1521 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for OSV-2020-1521 and fix it if it is affected.

What it is: OSV-2020-1521 is a vulnerability in stb, published on 28 Jul 2020. 
Exploitation: There is no known exploitation of OSV-2020-1521 in the wild and no public exploit code.

Affected packages and fixed versions:
- stb (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-2020-1521/ (Markdown: https://insights.sbomify.com/OSV-2020-1521/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/OSV-2020-1521

---
From sbomify Insights: https://insights.sbomify.com/OSV-2020-1521/
Summaries are generated and may contain mistakes; the official description above is the record.