GMS-2023-1803: Cross-Site Scripting in CKEditor4 WordCount Plugin

CVSS: `.4)

Problem

The WordCount plugin (npm:ckeditor-wordcount-plugin) for CKEditor4 is vulnerable to cross-site scripting when switching to the source code mode. This plugin is enabled via the Full.yaml configuration present, but is not active in the default configuration.

In default scenarios, exploiting this vulnerability requires a valid backend user account. However, if custom plugins are used on the website frontend, which accept and reflect rich-text content submitted by users, no authentication is required.

Solution

Update to TYPO3 versions 9.5.42 ELTS, 10.4.39 ELTS, 11.5.30 that fix the problem described above.

Credits

Thanks to Sybille Peters who reported this issue, and to TYPO3 core & security team member Oliver Hader who fixed the issue.

References

• TYPO3-CORE-SA-2023-004
• https://github.com/w8tcha/CKEditor-WordCount-Plugin/security/advisories/GHSA-q9w4-w667-qqj4