SmarterTools SmarterMail 8495 through 8664 before 8747 allows stored XSS by using image/svg+xml and an uploaded SVG document. This occurs because the application tries to allow youtube.com URLs, but actually allows youtube.com followed by an @ character and an attacker-controlled domain name.

SmarterTools SmarterMail 8495 through 8664 before 8747 allows stored XSS via a crafted description of a Calendar appointment.

SmarterTools SmarterMail 8495 through 8664 before 8747 allows stored DOM XSS because an XSS protection mechanism is skipped when messageHTML and messagePlainText are set in the same request.