The Jargon File (version 4.4.7, 29 Dec 2003):

leaky heap
 n.

    [Cambridge] An arena with a memory leak.


The Free On-line Dictionary of Computing (30 December 2018):

memory leak
core leak
leaky heap

    A leak in a program's dynamic store
   allocation logic that causes it to fail to reclaim memory in
   the heap after it has finished using it, eventually causing
   the program to fail due to lack of memory.

   These problems were severe on older machines with small,
   fixed-size address spaces, and special "leak detection" tools
   were written to diagnose them.

   The introduction of virtual memory made memory leaks a less
   serious problem, although if you run out of virtual
   memory, it means you've got a *real* leak!

   See aliasing bug.

   [Jargon File]

   (2003-10-07)