# GHSA-96jg-pmc4-cx39: TYPO3 CMS Insecure Deserialization

> Authenticated backend users can achieve remote code execution via insecure deserialization in the TYPO3 Form Framework when using the yaml PECL package.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 May 2024

## What is GHSA-96jg-pmc4-cx39?

GHSA-96jg-pmc4-cx39 is an unsafe deserialization vulnerability in typo3/cms-core, published on 30 May 2024. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

It has been discovered that the Form Framework (system extension `form`) is vulnerable to Insecure Deserialization when being used with the additional PHP PECL package `yaml`, which is capable of unserializing YAML contents to PHP objects. A valid backend user account as well as having PHP setting `yaml.decode_php` enabled is needed to exploit this vulnerability (which is the default value according to PHP documentation).

## Which versions are affected by GHSA-96jg-pmc4-cx39?

4 open source packages ship an affected version, including typo3/cms-core.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `typo3/cms-core` | Packagist | From 8.5.0 | 8.7.17 |
| `typo3/cms-core` | Packagist | From 8.5.0 | 8.7.17 |
| `typo3/cms-core` | Packagist | From 9.0.0 | 9.3.1 |
| `typo3/cms-core` | Packagist | From 9.0.0 | 9.3.1 |

## How do I fix GHSA-96jg-pmc4-cx39?

Upgrade typo3/cms-core to a fixed version for your release line: 8.7.17 or 9.3.1.

## Is GHSA-96jg-pmc4-cx39 being exploited?

There is no known exploitation of GHSA-96jg-pmc4-cx39 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-96jg-pmc4-cx39 and fix it if it is affected.

What it is: GHSA-96jg-pmc4-cx39 is an unsafe deserialization vulnerability in typo3/cms-core, published on 30 May 2024. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of GHSA-96jg-pmc4-cx39 in the wild and no public exploit code.

Affected packages and fixed versions:
- typo3/cms-core (Packagist): affected from 8.5.0; fixed in 8.7.17
- typo3/cms-core (Packagist): affected from 8.5.0; fixed in 8.7.17
- typo3/cms-core (Packagist): affected from 9.0.0; fixed in 9.3.1
- typo3/cms-core (Packagist): affected from 9.0.0; fixed in 9.3.1

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-96jg-pmc4-cx39/ (Markdown: https://insights.sbomify.com/GHSA-96jg-pmc4-cx39/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-96jg-pmc4-cx39

---
From sbomify Insights: https://insights.sbomify.com/GHSA-96jg-pmc4-cx39/
Summaries are generated and may contain mistakes; the official description above is the record.