The EWWW Image Optimizer WordPress plugin before 8.8.0 does not prevent authenticated users with author-level permissions from storing a serialized value in a post meta field that is deserialized when the post is rendered, allowing them to perform PHP Object Injection, which can lead to remote code execution when a suitable gadget chain is present via another installed EWWW Image Optimizer WordPress plugin before 8.8.0 or .

Contributor Cross Site Scripting (XSS) in EWWW Image Optimizer <= 8.7.7 versions.

The EWWW Image Optimizer plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via REQUESTURI Parameter Key in all versions up to, and including, 8.7.7 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. Successful exploitation requires that the enablehelp option is active, as the vulnerable HelpScout Beacon script block is only emitted when that setting is enabled.