Cross site scripting (XSS) vulnerability using authentication callback in Misskey

Misskey is an open source, decentralized social media platform. Due to insufficient validation of the redirect URL during miauth authentication in Misskey, arbitrary JavaScript can be executed when a user allows the link. All versions below 13.3.1 (including 12.x) are affected. This has been fixed in version 13.3.1. Users are advised to upgrade. Users unable to upgrade should not allow authentication of untrusted apps.