Security researcher Sabri Haddouche has discovered a collection of vulnerabilities affecting more than 30 popular email client software. Vulnerable clients include Apple Mail (macOS, iOS and watchOS), Mozilla Thunderbird, several Microsoft email clients, Yahoo Mail, ProtonMail, and others. MailSploit flaws affect the way email clients and web interfaces parse From header. The bugs are not detected by Mail Transfer Agents (MTA) aka email servers, therefore circumventing spoofing protection mechanisms such as DMARC or spam filters.”]
Source: https://securityaffairs.co/wordpress/66385/hacking/mailsploit-flaws-email-spoofing.html