GiveWP < 4.16.8.1 - Unauthenticated Account Takeover via Donor Email Sanitization Mismatch

Description

The plugin does not consistently normalise a donor's e-mail address between the value it stores and the value it later uses to look that donor up, allowing unauthenticated users to be resolved as an arbitrary donor and to set the WordPress password of any user account linked to one, including an administrator's.