WordPress through 4.9.6 allows Author users to execute arbitrary code by leveraging directory traversal in the wp-admin/post.php thumb parameter, which is passed to the PHP unlink function and can delete the wp-config.php file. This is related to missing filename validation in the wp-includes/post.php wp_delete_attachment function. The attacker must have capabilities for files and posts that are normally available only to the Author, Editor, and Administrator roles. The attack methodology is to delete wp-config.php and then launch a new installation process to increase the attacker's privileges.

Before WordPress 4.9.5, the version string was not escaped in the get_the_generator function, and could lead to XSS in a generator tag.

Before WordPress 4.9.5, the URL validator assumed URLs with the hostname localhost were on the same host as the WordPress server.

Before WordPress 4.9.5, the redirection URL for the login page was not validated or sanitized if forced to use HTTPS.

WordPress before 4.4 makes it easier for remote attackers to predict password-recovery tokens via a brute-force approach.

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.

WordPress before 4.9.2 has XSS in the Flash fallback files in MediaElement (under wp-includes/js/mediaelement).

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/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.