TYPO3-EXT-SA-2026-013: Remote Code Execution in extension "Content Element Selector" (ceselector)
It has been discovered that the extension "Content Element Selector" (ceselector) is vulnerable to Remote Code Execution.
- Release Date: May 19, 2026
- Component Type: Third party extension. This extension is not a part of the TYPO3 default installation.
- Component: "Content Element Selector" (ceselector)
- Composer Package Name: mmc/ceselector
- Vulnerability Type: Insecure Deserialization
- Affected Versions: 6.0.0, 5.0.0, 4.0.0 - 4.0.1, 3.0.2 and below
- Severity: Critical
- Suggested CVSS v4.0: AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- References: CVE-2026-46725, CWE-502
Problem Description
The extension fails to safely process untrusted client input of an attacker-controlled cookie directly to PHP's unserialize(). A remote, unauthenticated attacker can supply a crafted serialized payload to trigger PHP Object Injection, leading to Remote Code Execution on the TYPO3 server.
Exploitation requires the content element to be configured with "Persistent Mode: Static" in the plugin settings.
Solution
Updated versions 6.0.1, 5.0.1, 4.0.2 and 3.0.3 are available from the TYPO3 extension manager, packagist and at
https://extensions.typo3.org/extension/download/ceselector/6.0.1/zip
https://extensions.typo3.org/extension/download/ceselector/5.0.1/zip
https://extensions.typo3.org/extension/download/ceselector/4.0.2/zip
https://extensions.typo3.org/extension/download/ceselector/3.0.3/zip
Users of the extension are advised to update the extension as soon as possible.
Credits
Thanks to TYPO3 Security Team member Torben Hansen for reporting the vulnerability and to Matthias Mächler for providing updated versions of the extension.
General Advice
Follow the recommendations that are given in the TYPO3 Security Guide. Please subscribe to the typo3-announce mailing list.