Airmail 3 has been exposed for being vulnerable to hackers, who can extract users emails using a trojan email message. A simple malformed link can grant access to all the email messages to the attackers almost instantly. The flaw was discovered in the MacOS version of the app, while as of this writing it is still unknown if the iOS version is also vulnerable. The vulnerability came from its use of the same specific location for storing emails, a very visible and unchanging location ripe for attacks from outside the network.”]
Source: https://hackercombat.com/macos-airmail-3-app-vulnerable-to-email-leaks/