The Co-Authors, Multiple Authors and Guest Authors in an Author Box with PublishPress Authors plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'name (maps to display_name)' parameter in all versions up to, and including, 4.17.0 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Exploitation requires the attacker's user account to have a mapped author term, which occurs when an administrator has assigned them as a co-author on content or has enabled automatic author term creation for their role — this mapping is not present by default for new users on a stock install.