Citrix ShareFile before 19.12 allows User Enumeration. It is possible to enumerate application username based on different server responses using the request to check the otp code. No authentication is required.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-7217
Reference (s):
- http://www.sk-it.com/en/cve.html