An issue was discovered in the PageTriage extension in MediaWiki before 1.35.14, 1.36.x through 1.39.x before 1.39.6, and 1.40.x before 1.40.2. XSS can occur via the rev-deleted-user, pagetriage-tags-quickfilter-label, pagetriage-triage, pagetriage-filter-date-range-format-placeholder, pagetriage-filter-date-range-to, pagetriage-filter-date-range-from, pagetriage-filter-date-range-heading, pagetriage-filter-set-button, or pagetriage-filter-reset-button message.
https://phabricator.wikimedia.org/T347704
https://gerrit.wikimedia.org/r/c/mediawiki/extensions/PageTriage/+/989177