Frappe is a full-stack web application framework. Prior to 14.100.1, 15.100.0, and 16.6.0, a malicious user could send a crafted request to an endpoint which would lead to the server making an HTTP call to a service of the user's choice. This vulnerability is fixed in 14.100.1, 15.100.0, and 16.6.0.
https://github.com/frappe/frappe/security/advisories/GHSA-mggg-hmjm-j6c2