# GHSA-hh95-5xm5-v8v7: TYPO3 CMS Possible Insecure Deserialization in Extbase Request Handling

> Attackers with a leaked encryption key can exploit insecure deserialization in TYPO3 Extbase to execute arbitrary code.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 7 Jun 2024

## What is GHSA-hh95-5xm5-v8v7?

GHSA-hh95-5xm5-v8v7 is an unsafe deserialization vulnerability in typo3/cms, published on 7 Jun 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

It has been discovered that request handling in Extbase can be vulnerable to insecure deserialization. User submitted payload has to be signed with a corresponding HMAC-SHA1 using the sensitive TYPO3 encryptionKey as secret - invalid or unsigned payload is not deserialized.

However, since sensitive information could have been leaked by accident (e.g. in repositories or in commonly known and unprotected backup files), there is the possibility that attackers know the private encryptionKey and are able to calculate the required HMAC-SHA1 to allow a malicious payload to be deserialized.

Requirements for successfully exploiting this vulnerability (all of the following):

- rendering at least one Extbase plugin in the frontend
- encryptionKey has been leaked (from LocalConfiguration.php or corresponding .env file)

## Which versions are affected by GHSA-hh95-5xm5-v8v7?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `typo3/cms` | Packagist | From 8.0.0 | 8.7.30 |
| `typo3/cms` | Packagist | From 8.0.0 | 8.7.30 |
| `typo3/cms` | Packagist | From 9.0.0 | 9.5.12 |
| `typo3/cms` | Packagist | From 9.0.0 | 9.5.12 |

## How do I fix GHSA-hh95-5xm5-v8v7?

Upgrade typo3/cms to a fixed version for your release line: 8.7.30 or 9.5.12.

## Is GHSA-hh95-5xm5-v8v7 being exploited?

There is no known exploitation of GHSA-hh95-5xm5-v8v7 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-hh95-5xm5-v8v7 and fix it if it is affected.

What it is: GHSA-hh95-5xm5-v8v7 is an unsafe deserialization vulnerability in typo3/cms, published on 7 Jun 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of GHSA-hh95-5xm5-v8v7 in the wild and no public exploit code.

Affected packages and fixed versions:
- typo3/cms (Packagist): affected from 8.0.0; fixed in 8.7.30
- typo3/cms (Packagist): affected from 8.0.0; fixed in 8.7.30
- typo3/cms (Packagist): affected from 9.0.0; fixed in 9.5.12
- typo3/cms (Packagist): affected from 9.0.0; fixed in 9.5.12

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-hh95-5xm5-v8v7/ (Markdown: https://insights.sbomify.com/GHSA-hh95-5xm5-v8v7/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-hh95-5xm5-v8v7

---
From sbomify Insights: https://insights.sbomify.com/GHSA-hh95-5xm5-v8v7/
Summaries are generated and may contain mistakes; the official description above is the record.