The WP Webhooks plugin for WordPress is vulnerable to arbitrary file copy due to missing validation of user-supplied input in all versions up to, and including, 3.3.5. This makes it possible for unauthenticated attackers to copy arbitrary files on the affected site's server to arbitrary locations. This can be used to copy the contents of wp-config.php into a text file which can then be accessed in a browser to reveal database credentials.
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.