CVE-2026-50128

Mastodon is a free, open-source social network server based on ActivityPub. From 4.3.0 until 4.5.11 and 4.4.18, Mastodon has a feature to let websites credit authors of their articles. To prevent false attribution claims, Mastodon uses the attributionDomains JSON-LD term, however, an error in how...

CVE-2026-50128

Mastodon vulnerability CVE-2026-50128 affects versions 4.3.0 through 4.5.11 and 4.4.18, where an error in the attributionDomains JSON-LD handling allows an attacker to arbitrarily modify the attributionDomains value on a legitimately signed Update and bypass signature verification. This can under...