In Eclipse OpenJ9 release versions prior to 0.44.0 and after 0.13.0, when running with JVM option -Xgc:concurrentScavenge, the sequence generated for System.arrayCopy on the IBM Z platform with hardware and software support for guarded storage [1], could allow access to a buffer with an incorrect length value when executing an arraycopy sequence while the Concurrent Scavenge Garbage Collection cycle is active and the source and destination memory regions for arraycopy overlap. This allows read and write to addresses beyond the end of the array range.