The Flying Images: Optimize and Lazy Load Images for Faster Page Speed plugin for WordPress is vulnerable to Stored Cross-Site Scripting via admin settings in all versions up to, and including, 2.4.14 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.
https://plugins.trac.wordpress.org/changeset/3386814/nazy-load
https://plugins.svn.wordpress.org/nazy-load/tags/2.4.14/settings/lazyload.php
https://plugins.svn.wordpress.org/nazy-load/tags/2.4.14/settings/index.php
https://plugins.svn.wordpress.org/nazy-load/tags/2.4.14/inject-js.php