EWWW Image Optimizer < 8.7.4 - Contributor+ Stored XSS via 'data-script' Lazy Load Attribute in Post Content

Description

The plugin is vulnerable to Stored Cross-Site Scripting via the 'data-script' Lazy Load attribute in post content, due to insufficient input sanitization and output escaping. 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. The exploit is achieved by embedding a crafted img element with class='lazyload' and a data-script attribute pointing to an attacker-controlled URL in post content, which the plugin's bundled lazysizes ls.unveilhooks addon then uses to dynamically create and insert a script element into the DOM at page view time.