CVE-2021-41183: XSS in `*Text` options of the Datepicker widget in jquery-ui

Impact

Accepting the value of various *Text options of the Datepicker widget from untrusted sources may execute untrusted code. For example, initializing the datepicker in the following way:

$( "#datepicker" ).datepicker( {
	showButtonPanel: true,
	showOn: "both",
	closeText: "<script>doEvilThing( 'closeText XSS' )</script>",
	currentText: "<script>doEvilThing( 'currentText XSS' )</script>",
	prevText: "<script>doEvilThing( 'prevText XSS' )</script>",
	nextText: "<script>doEvilThing( 'nextText XSS' )</script>",
	buttonText: "<script>doEvilThing( 'buttonText XSS' )</script>",
	appendText: "<script>doEvilThing( 'appendText XSS' )</script>",
} );

will call doEvilThing with 6 different parameters coming from all *Text options.

Patches

The issue is fixed in jQuery UI 1.13.0. The values passed to various *Text options are now always treated as pure text, not HTML.

Workarounds

A workaround is to not accept the value of the *Text options from untrusted sources.

For more information

If you have any questions or comments about this advisory, search for a relevant issue in the jQuery UI repo. If you don't find an answer, open a new issue.