CVE-2021-29456: URL Redirection to Untrusted Site ('Open Redirect')

Utilizing a HTTP query parameter an attacker is able to redirect users from the web application to any domain. The URL of the intended redirect should always be checked for safety prior to forwarding the user. Other endpoints of the web application already do this, they check both that the domain is using the HTTPS protocol and that it exists on a domain associated with the application. An attacker is able to use this unintended functionality to redirect users to malicious sites. This particular security issue allows the attacker to make a phishing attempt seem much more trustworthy to a user of the web application as the initial site before redirection is familiar to them, as well as the actual URL which they have theoretically visited frequently.