MDaemon Mail Server 23.5.2 validates SPF, DKIM, and DMARC using the email enclosed in angle brackets (<>) in the From: header of SMTP DATA. An attacker can craft a From: header with multiple invisible Unicode thin spaces to display a spoofed sender while passing validation, allowing email spoofing even when anti-spoofing protections are in place. NOTE: this is disputed by the Supplier because UI spoofing occurs in a client, not in a server such as MDaemon's product or any other server implementation. Also, if a client without its own spoofing protection must be used, the Header Screening feature in MDaemon's product can be employed to mitigate the client-side vulnerability.

Stored XSS vulnerability in MDaemon Email Server

An XSS issue was discovered in MDaemon Email Server version 25.0.1 and below. An attacker can send a specially crafted HTML e-mail message with JavaScript in an img tag. This could allow a remote attacker to load arbitrary JavaScript code in the context of a webmail user's browser window, and access user data.