MikroTik RouterOS before 6.43.12 (stable) and 6.42.12 (long-term) is vulnerable to an intermediary vulnerability. The software will execute user defined network requests to both WAN and LAN clients. A remote unauthenticated attacker can use this vulnerability to bypass the router's firewall or for general network scanning activities.
https://www.tenable.com/security/research/tra-2019-07