The Clone plugin for WordPress, used to create an exact copy of a WordPress website, is vulnerable to a security problem called Cross-Site Request Forgery. This means that versions of the plugin up to and including 2.3.7 are affected. The issue arises because the plugin does not validate an important security measure called a ‘nonce’ correctly. This can allow an attacker to force a site administrator to do something, such as clicking on a link, and then change the ‘Test new plugins before installing’ setting without them knowing.