The FastSpring plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'fastspring/block-fastspringblocks-complete-product-catalog' block in all versions up to, and including, 3.0.1 due to insufficient input sanitization and output escaping on the 'color' attribute. 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.
CWE-79