In MediaWiki before 1.31.10 and 1.32.x through 1.34.x before 1.34.4 XSS related to jQuery can occur. The attacker creates a message with javascript:payload xss and turns it into a jQuery object with mw.message().parse(). The expected result is that the jQuery object does not contain an <a> tag (or it does not have a href attribute or it's empty etc.). The actual result is that the object contains an <a href =\javascript... that executes when clicked.