TinyMCE Custom Styles < 1.1.4 – Admin+ Stored Cross-Site Scripting

Description

The plugin 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).

Proof of Concept

1. Go to "Settings" »  "TinyMCE Custom Styles" section.

2. In the "2. Manage your custom styles for TinyMCE's Formats dropdown" area under the "Title" and "Type Value" fields add payload: "><script>alert(1);</script>

3. Save all the settings. Load the page,and an alert box with the number "1" will pop up.