In WordPress through 4.9.2, unauthenticated attackers can cause a denial of service (resource consumption) by using the large list of registered .js files (from wp-includes/script-loader.php) to construct a series of requests to load every file many times.
wp-admin/user-new.php in WordPress before 4.9.1 sets the newbloguser key to a string that can be directly derived from the user ID, which allows remote attackers to bypass intended access restrictions by entering this string.
wp-includes/functions.php in WordPress before 4.9.1 does not require the unfiltered_html capability for upload of .js files, which might allow remote attackers to conduct XSS attacks via a crafted file.
wp-includes/general-template.php in WordPress before 4.9.1 does not properly restrict the lang attribute of an HTML element, which might allow attackers to conduct XSS attacks via the language setting of a site.
wp-includes/feed.php in WordPress before 4.9.1 does not properly restrict enclosures in RSS and Atom fields, which might allow attackers to conduct XSS attacks via a crafted URL.