Data layout is the way information is arranged in memory: the order of fields, the size of each value, alignment padding, and how structures, arrays, or strings are placed next to each other. It is a background detail of programming, but it strongly affects how software reads and writes data.
In cybersecurity, data layout matters because many bugs begin when code makes the wrong assumption about that arrangement. A parser may read past a field boundary, a program may mis-handle a type conversion, or a vulnerable function may copy more bytes than a buffer can hold. Attackers look for these mistakes to trigger corruption, leak secrets, or influence control flow. Defenders study data layout to review unsafe memory handling, harden serialization formats, and spot mismatches between a program’s model and the actual bytes in memory.