Autoptimize < 3.1.16 - Unauthenticated Stored XSS via REQUEST_URI Path

Description

The plugin is vulnerable to Stored Cross-Site Scripting via REQUEST_URI Path due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Exploitation requires the Critical CSS feature to be active with a valid API key configured, as this is the precondition for unauthenticated frontend requests to trigger queue entries via ao_ccss_enqueue().