# GHSA-4fx9-vc88-q2xc: Infinite loop in Pillow

> An attacker can cause a denial of service via infinite loop in Pillow by providing a truncated JPEG file that bypasses EOF detection.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 11 Mar 2022

## What is GHSA-4fx9-vc88-q2xc?

GHSA-4fx9-vc88-q2xc is a denial of service vulnerability in Pillow, published on 11 Mar 2022. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

JpegImagePlugin may append an EOF marker to the end of a truncated file, so that the last segment of the data will still be processed by the decoder.

If the EOF marker is not detected as such however, this could lead to an infinite loop where JpegImagePlugin keeps trying to end the file.

## Which versions are affected by GHSA-4fx9-vc88-q2xc?

2 open source packages ship an affected version, including Pillow and pillow.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Pillow` | PyPI | All versions | 9.0.0 |
| `pillow` | PyPI | All versions | 9.0.0 |

## How do I fix GHSA-4fx9-vc88-q2xc?

Upgrade Pillow to 9.0.0 or later.

## Is GHSA-4fx9-vc88-q2xc being exploited?

There is no known exploitation of GHSA-4fx9-vc88-q2xc in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-4fx9-vc88-q2xc and fix it if it is affected.

What it is: GHSA-4fx9-vc88-q2xc is a denial of service vulnerability in Pillow, published on 11 Mar 2022. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of GHSA-4fx9-vc88-q2xc in the wild and no public exploit code.

Affected packages and fixed versions:
- Pillow (PyPI): affected all versions; fixed in 9.0.0
- pillow (PyPI): affected all versions; fixed in 9.0.0

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/GHSA-4fx9-vc88-q2xc/ (Markdown: https://insights.sbomify.com/GHSA-4fx9-vc88-q2xc/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-4fx9-vc88-q2xc

---
From sbomify Insights: https://insights.sbomify.com/GHSA-4fx9-vc88-q2xc/
Summaries are generated and may contain mistakes; the official description above is the record.