TYPO3-EXT-SA-2025-003: Multiple vulnerabilities in extension “[clickstorm] SEO” (cs_seo)

Categories: Development Created by Torben Hansen
It has been discovered that the extension "[clickstorm] SEO" (cs_seo) is susceptible to Cross-Site Scripting and Insecure Direct Object Reference.

Problem Description

The extension fails to properly encode user input for output in HTML context in TYPO3 backend user interface. Additionally, the SEO file module fails to verify whether a user is allowed to view or modify file metadata of a specified file identifier resulting in Broken Access Control and Insecure Direct Object Reference.

Note, that all vulnerabilities can only be exploited by a logged in backend user.

Solution

Updated versions 6.7.0, 7.4.0, 8.3.0 and 9.2.0 are available from the TYPO3 extension manager, packagist and at
https://extensions.typo3.org/extension/download/cs_seo/6.7.0/zip
https://extensions.typo3.org/extension/download/cs_seo/7.4.0/zip
https://extensions.typo3.org/extension/download/cs_seo/8.3.0/zip
https://extensions.typo3.org/extension/download/cs_seo/9.2.0/zip

Users of the extension are advised to update the extension as soon as possible.

Additionally, the TYPO3 Security Team recommends enabling the Content Security Policy (CSP) for the TYPO3 backend user interface in TYPO3 12.4. In TYPO3 13.4, this security feature is enabled by default.

Credits

Thanks to the Swiss NCSC Vulnerability Management Team for reporting the Cross-Site Scripting issue, to TYPO3 Security Team Member Torben Hansen for reporting the IDOR vulnerabilities and to Marc Hirdes  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.