The Social Share Buttons & Analytics Plugin – GetSocial.io plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'response' parameter in all versions up to, and including, 4.5 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The injected payload is stored in the gs-alert-msg, gs-alert-utm, and gs-alert-cta WordPress options and executes in an administrator's browser when the GetSocial settings page is visited.