Malicious Javascript injection in OriginProtocol/origin-website

Origin Protocol is a blockchain based project. The Origin Protocol project website allows for malicious users to inject malicious Javascript via a POST request to /presale/join. User-controlled data is passed with no sanitization to SendGrid and injected into an email that is delivered to the founders@originprotocol.com. If the email recipient is using an email program that is susceptible to XSS, then that email recipient will receive an email that may contain malicious XSS. Regardless if the email recipient’s mail program has vulnerabilities or not, the hacker can at the very least inject malicious HTML that modifies the body content of the email. There are currently no known workarounds.