Cross-site scripting (XSS) in the clipboard package
Date: 2024-09
Affected: npm/@ckeditor/ckeditor5-clipboard, npm/ckeditor5
Attack vector: xss
Category: vulnerability-disclosure
Severity: Medium
CVE: CVE-2024-45613
CWE: CWE-79
CVSS: 7.2 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N)

### Impact 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: 1. The [**Block Toolbar**](https://ckeditor.com/docs/ckeditor5/latest/getting-started/setup/toolbar.html#block-toolbar) plugin is enabled. 1. One of the following plugins is also enabled: - [**General HTML Support**](https://ckeditor.com/docs/ckeditor5/latest/features/html/general-html-support.html) with a configuration that permits unsafe markup. - [**HTML Embed**](https://ckeditor.com/docs/ckeditor5/latest/features/html/html-embed.html). ### Patches The problem has been recognized and patched. The fix will be available in version 43.1.1 (and above), and explicitly in version 41.3.2. ### Workarounds It's highly recommended to update to the version 43.1.1 or higher. However, if the update is not an option, we recommend disabling the block toolbar plugin. ### For more information Email us at [security@cksource.com](mailto:security@cksource.com) if you have any questions or comments about this advisory.


Mitigations:

Architectural layers (MAESTRO):