A method for specifying areas of memory that cannot be used for execution. Supported by the CPU's virtual memory function, the bit is a flag (an indicator) in a virtual memory page. It can be used to isolate memory for storage versus instructions, as well as a security measure to ensure that malware instructions are not executed in memory areas where only data are expected to reside.
NX, XD and XN
Depending on the architecture, the never execute bit is called "NX" (never execute), "XD" (execute disable) or "XN" (execute never). See virtual memory
. See also no-op