TinyMCE versions before 5.9.0 are affected by a stored cross-site scripting vulnerability. An unauthenticated and remote attacker could insert crafted HTML into the editor resulting in arbitrary JavaScript execution in another user's browser.

TinyMCE is an open source rich text editor. A mutation cross-site scripting (mXSS) vulnerability was discovered in TinyMCE’s core undo/redo functionality and other APIs and plugins. Text nodes within specific parents are not escaped upon serialization according to the HTML standard. If such text nodes contain a special character reserved as an internal marker, they can be combined with other HTML patterns to form malicious snippets. These snippets pass the initial sanitisation layer when the content is parsed into the editor body, but can trigger XSS when the special internal marker is removed from the content and re-parsed. his vulnerability has been patched in TinyMCE versions 6.7.3 and 5.10.9. Users are advised to upgrade. There are no known workarounds for this vulnerability.

TinyMCE is an open source rich text editor. A cross-site scripting (XSS) vulnerability was discovered in TinyMCE’s Notification Manager API. The vulnerability exploits TinyMCE's unfiltered notification system, which is used in error handling. The conditions for this exploit requires carefully crafted malicious content to have been inserted into the editor and a notification to have been triggered. When a notification was opened, the HTML within the text argument was displayed unfiltered in the notification. The vulnerability allowed arbitrary JavaScript execution when an notification presented in the TinyMCE UI for the current user. This issue could also be exploited by any integration which uses a TinyMCE notification to display unfiltered HTML content. This vulnerability has been patched in TinyMCE 5.10.8 and TinyMCE 6.7.1 by ensuring that the HTML displayed in the notification is sanitized, preventing the exploit. Users are advised to upgrade. There are no known workarounds for th…

TinyMCE is an open source rich text editor. A mutation cross-site scripting (mXSS) vulnerability was discovered in TinyMCE’s core undo and redo functionality. When a carefully-crafted HTML snippet passes the XSS sanitisation layer, it is manipulated as a string by internal trimming functions before being stored in the undo stack. If the HTML snippet is restored from the undo stack, the combination of the string manipulation and reparative parsing by either the browser's native [DOMParser API](https://developer.mozilla.org/en-US/docs/Web/API/DOMParser) (TinyMCE 6) or the SaxParser API (TinyMCE 5) mutates the HTML maliciously, allowing an XSS payload to be executed. This vulnerability has been patched in TinyMCE 5.10.8 and TinyMCE 6.7.1 by ensuring HTML is trimmed using node-level manipulation instead of string manipulation. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Cross-Site Request Forgery (CSRF) vulnerability in Kvvaradha Kv TinyMCE Editor Add Fonts plugin <= 1.1 versions.

The TinyMCE Custom Styles WordPress plugin before 1.1.4 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup).

Auth. (admin+) Stored Cross-Site Scripting (XSS) vulnerability in Tim Reeves & David Stöckl TinyMCE Custom Styles plugin <= 1.1.2 versions.

tinymce is an open source rich text editor. A cross-site scripting (XSS) vulnerability was discovered in the alert and confirm dialogs when these dialogs were provided with malicious HTML content. This can occur in plugins that use the alert or confirm dialogs, such as in the `image` plugin, which presents these dialogs when certain errors occur. The vulnerability allowed arbitrary JavaScript execution when an alert presented in the TinyMCE UI for the current user. This vulnerability has been patched in TinyMCE 5.10.7 and TinyMCE 6.3.1 by ensuring HTML sanitization was still performed after unwrapping invalid elements. Users are advised to upgrade to either 5.10.7 or 6.3.1. Users unable to upgrade may ensure the the `images_upload_handler` returns a valid value as per the images_upload_handler documentation.

The Custom TinyMCE Shortcode Button WordPress plugin through 1.1 does not sanitise and escape the PHP_SELF variable before outputting it back in an attribute in an admin page, leading to Reflected Cross-Site Scripting.

A cross-site scripting (XSS) vulnerability in TinyMCE 5.2.1 and earlier allows remote attackers to inject arbitrary web script when configured in classic editing mode.