Email parsing is the process of reading an email’s headers, body, attachments, and message structure so software can classify it, route it, filter it, or extract data from it. Security appliances, mail servers, and spam filters rely on parsing to decide whether a message is legitimate, malicious, or needs special handling.
In cyber security, parsing is a high-risk step because the input comes from untrusted senders. If a parser handles malformed MIME parts, unusual encodings, or crafted headers incorrectly, attackers may trigger crashes, bypass filtering, inject commands, or reach backend systems such as databases. Defenders harden this layer with strict validation, safe libraries, size limits, and sandboxing. Attackers often abuse parsing logic with specially crafted emails that look harmless to users but confuse automated processing before the message is delivered.