HomeBox: Forced Group Membership Without Consent in Homebox AddMember Handler

HomeBox is a home inventory and organization system. Prior to 0.26.0, POST /v1/groups/members invokes HandleGroupMemberAdd and GroupService.AddMember using a caller-supplied userID without requiring an owner role, an invitation token, target-user consent, or target-user notification. Any authenticated user can force another account into the caller's group, disclose the target user's email address and name through the resulting member list, and create the membership prerequisite used by a separate cross-group inventory-wipe vulnerability. This issue is fixed in version 0.26.0.