CVE-2026-63178 Onyx Curator-scope IDOR: any curator can modify membership of arbitrary user groups via unscoped PATCH /manage/admin/user-group/{id} and /add-users leading to cross-group document disclosure

Onyx is an open-source AI platform. Prior to 4.3.0, Onyx Enterprise Edition's PATCH /manage/admin/user-group/usergroupid and POST /manage/admin/user-group/usergroupid/add-users endpoints in ee/onyx/server/usergroup/api.py call updateusergroup and adduserstousergroup in ee/onyx/db/usergroup.py...