Ultimate Blocks – WordPress Blocks Plugin < 3.1.1 - Authenticated(Contributor+) Stored Cross-Site Scripting via metabox

Description

The Ultimate Blocks – WordPress Blocks Plugin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's tab anchor metabox in all versions up to, and including, 3.0.8 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers with contributor-level and above permissions to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.