Bucket is a MediaWiki extension to store and retrieve structured data on articles. Prior to 2.1.1, a stored XSS can be inserted into any Bucket table field that has a PAGE type, which will execute whenever a user views that table's corresponding Bucket namespace page. This vulnerability is fixed in 2.1.1.
Improper Neutralization of Input During Web Page Generation The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.