Guest Entries is a php library which allows users to create, update & delete entries from the front-end of a site. In affected versions the file uploads feature did not prevent the upload of PHP files. This may lead to code execution on the server by authenticated users. This vulnerability is fixed in v3.1.2. Users are advised to upgrade. There are no known workarounds for this vulnerability.
The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.