NextScripts: Social Networks Auto-Poster < 4.4.7 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'nxs_fbembed' Shortcode

Description

The NextScripts: Social Networks Auto-Poster plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the `[nxs_fbembed]` shortcode in all versions up to, and including, 4.4.6. This is due to insufficient input sanitization and output escaping on the `snapFB` post meta value. 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.