From The Free On-line Dictionary of Computing (19 January 2023):
leak
<programming> With a qualifier, one of a class of
resource-management bugs that occur when resources are not
freed properly after operations on them are finished, so they
effectively disappear (leak out). This leads to eventual
exhaustion as new allocation requests come in.
One might refer to, say, a "window handle leak" in a window
system.
See memory leak, fd leak.
(1995-04-18)