The Event Registration Calendar By vcita plugin, versions up to and including 3.9.1, and Online Payments – Get Paid with PayPal, Square & Stripe plugin, for WordPress are vulnerable to Stored Cross-Site Scripting via the 'email' parameter in versions up to, and including, 1.3.1 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers with the edit_posts capability, such as contributors and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.