Blog Floating Button <= 1.4.21 - Unauthenticated Stored XSS via User-Agent Header

Description

The plugin does not sanitize or escape the visitor User-Agent header, which it stores through an unauthenticated tracking REST endpoint and later renders unescaped in an administrator report page. This allows an unauthenticated attacker to store a malicious script that executes in the session of any administrator who views the access report, leading to site takeover.