A flaw was found in Rubygem MQTT. By default, the package used to not have hostname validation, resulting in possible Man-in-the-Middle (MITM) attack.
Exploitability
AV:NAC:HPR:NUI:NScope
S:UImpact
C:HI:HA:N7.4/CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:NOther