CVE-2019-11340

util/emailutils.py in Matrix Sydent before 1.0.2 mishandles registration restrictions that are based on e-mail domain, if the allowed_local_3pids option is enabled. This occurs because of potentially unwanted behavior in Python, in which an email.utils.parseaddr call on [email protected]@good.example.com returns the [email protected] substring.

Source: CVE-2019-11340