Systems & Memory
Use-After-Free
Also: UAF, CWE-416
Using a block of memory after it has been released, by which time it may belong to something else.
In more detail
A dangling pointer is read or written after free. Because allocators reuse blocks quickly, the stale access can read or corrupt data the new owner took from outside. Classified as CWE-416. Prevented by clear ownership, nulling pointers and memory-safe languages.