WordPress is an open publishing platform for the Web. Unserialization of instances of the WPHTMLToken class allows for code execution via its destruct() magic method. This issue was fixed in WordPress 6.4.2 on December 6th, 2023. Versions prior to 6.4.0 are not affected.

WordPress is an open publishing platform for the Web. It's possible for a file of a type other than a zip file to be submitted as a new plugin by an administrative user on the Plugins -> Add New -> Upload Plugin screen in WordPress. If FTP credentials are requested for installation (in order to move the file into place outside of the uploads directory) then the uploaded file remains temporary available in the Media Library despite it not being allowed. If the DISALLOWFILEEDIT constant is set to true on the site and FTP credentials are required when uploading a new theme or plugin, then this technically allows an RCE when the user would otherwise have no means of executing arbitrary PHP code. This issue only affects Administrator level users on single site installations, and Super Admin level users on Multisite installations where it's otherwise expected that the user does not have permission to upload or execute arbitrary PHP code. Lower level users are not affected. Sites where the DISALLOWFILEMODS constant is set to true are not affected. Sites where an administrative user either does not need to enter FTP credentials or they have access to the valid FTP credentials, are not affected. The issue was fixed in WordPress 6.4.3 on January 30, 2024 and backported to versions 6.3.3, 6.2.4, 6.1.5, 6.0.7, 5.9.9, 5.8.9, 5.7.11, 5.6.13, 5.5.14, 5.4.15, 5.3.17, 5.2.20, 5.1.18, 5.0.21, 4.9.25, 2.8.24, 4.7.28, 4.6.28, 4.5.31, 4.4.32, 4.3.33, 4.2.37, and 4.1.40. A workaround is available. If the DISALLOWFILEMODS constant is defined as true then it will not be possible for any user to upload a plugin and therefore this issue will not be exploitable.

WordPress Core is vulnerable to Stored Cross-Site Scripting via user display names in the Avatar block in various versions up to 6.5.2 due to insufficient output escaping on the display name. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. In addition, it also makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that have the comment block present and display the comment author's avatar.