CWE-415 is MITRE’s identifier for a double free weakness: software releases the same memory block twice. This usually happens in C and C++ code when error handling, cleanup paths, or pointer ownership are not carefully managed.
Double free bugs matter because they can corrupt the heap, crash a process, or create conditions that attackers may use for code execution. They often appear in parsers, network services, drivers, and embedded firmware, where complex state transitions make memory ownership easy to mishandle. Defenders look for CWE-415 with code review, fuzzing, sanitizers, and static analysis, and reduce risk by using clear ownership rules, setting freed pointers to null, and avoiding duplicate cleanup in multiple code paths.