# CVE-2026-8727: Remote Code Execution in extension "Site Crawler" (crawler)

> An attacker with admin privileges can achieve remote code execution on TYPO3 servers by injecting malicious serialized objects into crawled responses.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:A/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 19 May 2026
- **Updated:** 19 May 2026
- **Also known as:** GHSA-jr8m-x4p7-p3v5

## What is CVE-2026-8727?

CVE-2026-8727 is a high-severity unsafe deserialization vulnerability in TYPO3 Extension "Site Crawler", published on 19 May 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

The Crawler extension passes the X-T3Crawler-Meta response header from crawled URLs directly to PHP's unserialize(). An attacker controlling a crawled endpoint can inject arbitrary serialized PHP objects, leading to Remote Code Execution on the TYPO3 server. Exploitation requires administrative privileges to configure a crawler-enabled page and trigger the crawl via a Scheduler task.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-8727?

4 open source packages ship an affected version, including tomasnorre/crawler.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `tomasnorre/crawler` | Packagist | All versions | 11.0.13 |
| `tomasnorre/crawler` | Packagist | All versions | 11.0.13 |
| `tomasnorre/crawler` | Packagist | From 12.0.0 | 12.0.11 |
| `tomasnorre/crawler` | Packagist | From 12.0.0 | 12.0.11 |

## How do I fix CVE-2026-8727?

Upgrade tomasnorre/crawler to a fixed version for your release line: 11.0.13 or 12.0.11.

## Is CVE-2026-8727 being exploited?

There is no known exploitation of CVE-2026-8727 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-8727 and fix it if it is affected.

What it is: CVE-2026-8727 is a high-severity unsafe deserialization vulnerability in TYPO3 Extension "Site Crawler", published on 19 May 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-8727 in the wild and no public exploit code.

Affected packages and fixed versions:
- tomasnorre/crawler (Packagist): affected all versions; fixed in 11.0.13
- tomasnorre/crawler (Packagist): affected all versions; fixed in 11.0.13
- tomasnorre/crawler (Packagist): affected from 12.0.0; fixed in 12.0.11
- tomasnorre/crawler (Packagist): affected from 12.0.0; fixed in 12.0.11

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/CVE-2026-8727/ (Markdown: https://insights.sbomify.com/CVE-2026-8727/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-8727
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-8727
- OSV: https://osv.dev/vulnerability/CVE-2026-8727

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-8727/
Summaries are generated and may contain mistakes; the official description above is the record.