BIT-DISCOURSE-2026-33410 Discourse hardens chat DM channel creation and expansion

Discourse is an open-source discussion platform. Versions prior to 2026.3.0, 2026.2.1, and 2026.1.2 have two authorization issues in the chat direct message API. First, when creating a direct message channel or adding users to an existing one, the targetgroups parameter was passed directly to the...