Glossary
Threadjacking
Inserting a message into an existing email conversation so it looks like a legitimate reply.
ValidReach Team · Updated 2026-10-26
In practice
Attackers who control a mailbox reply in real threads with malicious links, which people trust. In marketing, a fake “Re:” subject to pretend an ongoing conversation is deceptive and can break the rules on misleading subject lines.
Verification and sending
Not related to verification; it is a security and honesty issue about message content.