Disposal
Defects in the lifetime of objects that hold unmanaged or scarce resources, where an IDisposable is allocated but never deterministically released. The garbage collector reclaims managed memory, but not file handles, sockets, database connections, or native buffers — those leak until a finalizer eventually runs, if one exists at all.
The fix is almost always a using statement or declaration that bounds the resource’s life to its scope; the defect is the path where that scope is missing and Dispose is left to chance.