Bypass auth.email-domains

How it was found

Email addresses are stored as VARCHAR(64). the length is verified on client side only , using a proxy(temper data) attacker can add longer length email which can be further abused .Exploiting this is rather straightforward: get an email address of 128 characters long . Now register with your 128 character email address with @allowed-domain.com appended to it. The @allowed-domain.com part will be truncated because MySQL can’t store it, and you will receive a verification email on your 128 character email address.

This is especially easy if you’re using a Gmail address: if you own [email protected], you’ll also receive any mails sent to attacker+aaaaaaaaaaa…[email protected].

snap attached : a POC for a truncated email address