The InstaWP Connect – 1-click WP Staging & Migration plugin for WordPress is vulnerable to authentication bypass in all versions up to, and including, 0.1.0.44. This is due to insufficient verification of the API key. This makes it possible for unauthenticated attackers to log in as any existing user on the site, such as an administrator, if they have access to the username, and to perform a variety of other administrative tasks. NOTE: This vulnerability was partially fixed in 0.1.0.44, but was still exploitable via Cross-Site Request Forgery.
https://plugins.trac.wordpress.org/changeset/3114674/