During a recent internal audit, we identified a Cross-Site Scripting (XSS) vulnerability in the CKEditor 5 clipboard package. This vulnerability could be triggered by a specific user action, leading to unauthorized JavaScript code execution, if the attacker managed to insert a malicious content into the editor, which might happen with a very specific editor configuration.
This vulnerability affects only installations where the editor configuration meets the following criteria:
The problem has been recognized and patched. The fix will be available in version 43.1.1.
It's highly recommended to update to the version 43.1.1. However, if the update is not an option, we recommend disabling the block toolbar plugin.
Email us at security@cksource.com if you have any questions or comments about this advisory.