Package Instance

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CKEditor4 is an open source WYSIWYG HTML editor. The vulnerability allowed to inject malformed HTML bypassing content sanitization, which could result in executing JavaScript code.

CKEditor 4 ReDoS Vulnerability
It was possible to execute a ReDoS-type attack inside CKEditor 4 before 4.16 by persuading a victim to paste crafted text into the Styles input of specific dialogs (in the Advanced Tab for Dialogs plugin).

Inclusion of Functionality from Untrusted Control Sphere in CKEditor 4
It was possible to execute a ReDoS-type attack inside CKEditor 4 before 4.16 by persuading a victim to paste crafted URL-like text into the editor, and then press Enter or Space (in the Autolink plugin).

Cross-site scripting (XSS) in the clipboard package
### 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.

Cross-site Scripting
ckeditor is an open source WYSIWYG HTML editor with rich content support. A potential vulnerability has been discovered in CKEdit The vulnerability allowed to inject malformed Fake Objects HTML, which could result in executing JavaScript code. It affects all users using the CKEditor 4 plugins listed above at The problem has been recognized and patched.

Improper Input Validation
CKEditor4 is an open source what-you-see-is-what-you-get HTML editor. CKEditor4 prior to version 4.18.0 contains a vulnerability in the `dialog` plugin. The vulnerability allows abuse of a dialog input validator regular expression, which can cause a significant performance drop resulting in a browser tab freeze. A patch is available in version 4.18.0. There are currently no known workarounds.