Medium · published September 2, 2026
Cypht before 2.12.2 contains a cross-site scripting vulnerability in the contacts module that allows remote attackers to execute arbitrary script content by embedding malicious payloads within angle brackets in the FROM email header. The sanitization logic removes only the first occurrence of each angle bracket character, leaving additional angle brackets intact, which attackers exploit by delivering a crafted email whose FROM header executes script in the victim's browser when the user opens the message and accesses the Add Local Contacts function.