SiteOrigin Widgets Bundle <= 1.58.3 - Authenticated (Contributor+) Stored Cross-Site Scripting

The SiteOrigin Widgets Bundle plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the onclick parameter in all versions up to, and including, 1.58.3 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers with contributor access or higher to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. 1.58.3 offers a partial fix.