Sometimes in order to reset a password you contact an api endpoint and send the email you want to reset the password, like in the following example:
The back-end may take the information present in the Host header and use it for the link where the token to reset the password is going to be sent.
For example, in this case if could send the reset password email to [email protected] and set the token link to https://bing.com/resetpasswd?token=12348rhfblrihvkurewfwu23
Example from https://medium.com/@abhishake100/password-reset-poisoning-to-ato-and-otp-bypass-1a3b0eba5491
In other occasions you can manage to obtain the same results modifying the domain used in the Referer header like in here.