A record delimiter is a separator that tells a parser where one message ends and the next begins in a stream of data. It can be a character, a sequence of bytes, or a structured framing marker. Delimiters are essential in protocols, logs, and local IPC because they let software split continuous input into discrete records without confusion.
Security problems appear when delimiter handling is weak. If untrusted text is inserted into a stream without escaping, an attacker may smuggle an extra delimiter and make one payload look like two messages. That can turn harmless input into a forged command, a fake parameter, or a new log entry. Defenses include strict escaping, length-based framing, clear message schemas, and rejecting mixed record types on the same channel. In practice, delimiter bugs often show up in desktop IPC, parsers, and export or import tools where trusted and untrusted data meet.