The Enable Media Replace plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the SHORTPIXEL_DEBUG parameter in all versions up to, and including, 4.1.4 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. Exploiting this vulnerability requires the attacker to know the ID of an attachment uploaded by the user they are attacking.

The Enable Media Replace WordPress plugin before 4.1.3 unserializes user input via the Remove Background feature, which could allow Author+ users to perform PHP Object Injection when a suitable gadget is present on the blog

The Enable Media Replace WordPress plugin before 4.0.2 does not prevent authors from uploading arbitrary files to the site, which may allow them to upload PHP shells on affected sites.

The Enable Media Replace WordPress plugin before 4.0.0 does not ensure that renamed files are moved to the Upload folder, which could allow high privilege users such as admin to move them outside to the web root directory via a path traversal attack for example