Open redirect via transitional IPv6 addresses on dual-stack networks

Impact Requests to user provided domains were not restricted to external IP addresses when transitional IPv6 addresses were used. Outbound requests to federation, identity servers, when calculating the key validity for third-party invite events, sending push notifications, and generating URL...

CVE-2021-21392

Synapse is a Matrix reference homeserver written in python pypi package matrix-synapse. Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.28.0 requests to user provided domains were not restricted to external IP addresses when transitional IPv6...