An XSS issue was discovered in MediaWiki before 1.35.6, 1.36.x before 1.36.4, and 1.37.x before 1.37.2. The widthheight, widthheightpage, and nbytes properties of messages are not escaped when used in galleries or Special:RevisionDelete.
An issue was discovered in MediaWiki before 1.35.5, 1.36.x before 1.36.3, and 1.37.x before 1.37.1. Special:CheckUserLog allows CheckUser XSS because of date mishandling, as demonstrated by an XSS payload in MediaWiki:October.
An issue was discovered in MediaWiki before 1.35.5, 1.36.x before 1.36.3, and 1.37.x before 1.37.1. Some unprivileged users can view confidential information (e.g., IP addresses and User-Agent headers for election traffic) on a testwiki SecurePoll instance.
An issue was discovered in MediaWiki before 1.35.5, 1.36.x before 1.36.3, and 1.37.x before 1.37.1. A denial of service (resource consumption) can be accomplished by searching for a very long key in a Language Name Search.
An issue was discovered in MediaWiki before 1.35.5, 1.36.x before 1.36.3, and 1.37.x before 1.37.1. The WikibaseMediaInfo component is vulnerable to XSS via the caption fields for a given media file.
In MediaWiki through 1.37, XSS can occur in Wikibase because an external identifier property can have a URL format that includes a $1 formatter substitution marker, and the javascript: URL scheme (among others) can be used.