Affected: npm: nodemailer

### Vulnerability summary

addressparser ends an angle-addr at the first `>` it sees, including one inside a quoted local part, a comment or a domain literal. The domain is then read off the text in front of that `>`. `<"a@evil.com>"@good.com>` is the mailbox `"a@evil.com>"@good.com` under RFC 5322, and Nodemailer read it as an address at `evil.com`. The unbracketed spelling of the same value was already read correctly. Affected: 3.0.0 through 10.1.3.

### Attacker capabilities

The attacker controls the text of a recipient or sender address that an application passes to Nodemailer, for example a To value entered in a contact or invite form, or the header of an inbound message parsed with mailparser. No access to the application, its configuration or its credentials is needed. The value is a syntactically valid RFC 5322 address that conformant parsers accept without defects.

### Realistic exploitation scenario

An application lets users send invitations or notifications only to addresses at an allowed domain and validates the submitted value with a conformant parser or by checking its domain. The attacker submits `<"a@evil.com>"@good.com>`, which validates as a `good.com` mailbox. Nodemailer then parses the same value, issues `RCPT TO:<"\"a"@evil.com>` and the message, with whatever content the application puts into it, is delivered to the attacker's domain. The security boundary crossed is the application's recipient allow list. In the inbound direction, mailparser reports…