BIT-MASTODON-2026-33868 Mastodon has a GET-Based Open Redirect via '/web/%2F<domain>'

Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.5.8, 4.4.15, and 4.3.21, an unauthenticated Open Redirect vulnerability CWE-601 exists in the /web/ route due to improper handling of URL-encoded path segments. An attacker can craft a specially encode...

EUVD-2026-16783

Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.5.8, 4.4.15, and 4.3.21, an unauthenticated Open Redirect vulnerability CWE-601 exists in the /web/ route due to improper handling of URL-encoded path segments. An attacker can craft a specially encode...