Spacebar Server before commit dcfd910 contains a missing authorization vulnerability that allows any authenticated attacker to add themselves to arbitrary group DM channels by sending a PUT request t…

摘要

Spacebar Server before commit dcfd910 contains a missing authorization vulnerability that allows any authenticated attacker to add themselves to arbitrary group DM channels by sending a PUT request to the channels recipient endpoint without membership verification. Attackers can exploit the unguarded PUT /channels/{channel_id}/recipients/{user_id} handler to join private group DMs, read complete message history, post messages as a participant, and force-add third-party users without their conse…

中文摘要建设中，暂以英文摘要呈现（DR-003 v2）。