Mikrotik RouterOS before 6.42.7 and 6.40.9 is vulnerable to stack buffer overflow through the license upgrade interface. This vulnerability could theoretically allow a remote authenticated attacker execute arbitrary code on the system.
https://github.com/JonathanInfinity01/SOC-L1-OSINT-Investigation-MikroTik-CVE-2018-1156
https://www.tenable.com/security/research/tra-2018-21
https://mikrotik.com/download/changelogs/bugfix-release-tree