Software program robustness is improved by successfully masking memory safety errors in the software program. For instance, at least some memory safety errors in a software program can be masked by using a runtime memory manager that approximates the semantics of an infinite heap memory manager. In one example, an approximation of an infinite heap memory manager is implemented by configuring a parameterized memory manager with parameter values such as padding to be added to each allocation on the heap and the amount of deferment before executing a call to free memory on the heap. Ideal configurations balance expected robustness with costs such as added memory and processing time. Ideal configurations can be identified through systematic search of a coordinate space of selected parameters. Ideal configurations can also be identified by statistically correlating success/failure data collected from execution of deployed instances of the software program to the configuration of the memory managers used therein.