Dangling Pointer
In plain terms
A pointer referencing memory that's been freed.
Going deeper
A dangling pointer still points to memory that has been deallocated, so using it causes undefined behavior or crashes. It references a ghost.
Under the hood
A common C/C++ bug and security risk (use-after-free); mitigated by nulling pointers or safer languages.
Examples
Use-after-free bugs, C/C++ crashes, memory safety, security vulnerabilities.
Think of it like...
Like a forwarding address for a house that's already been demolished.