Roxy-WI is a web interface for managing Haproxy, Nginx, Apache and Keepalived servers. In versions 8.2.6.4 and prior, PUT /smon/check (app/routes/smon/routes.py:117-138) gates only on roxywi_common.check_user_group_for_flask() — which validates that the caller has some group, not that the target check_id belongs to it. The downstream SQL update functions update_smon, update_smonHttp, update_smonTcp, update_smonPing, update_smonDns (app/modules/db/smon.py:515-562) all execute WHERE smon_id = ? with no user_group filter. The DELETE path is correctly filtered (app/modules/db/smon.py:319-327 does WHERE id = ? AND user_group = ?), demonstrating that the maintainers know the right pattern but did not apply it on UPDATE. Therefore any authenticated user can iterate over smon_id values and silently rewrite any other tenant's HTTP / TCP / Ping / DNS monitoring check. At time of publication, there are no publicly available patches.