A 'null pointer' is a link in software code that points to an empty location in computer memory.
Geoff Sweeney, chief executive at Tier-3, said: "Buffer overflows are still an issue, but they are a problem that has been tackled by the industry for many years.
"Null pointer de-referencing has not received anywhere near the same level of attention, which means that users need to be more vigilant than ever."
Sweeney added that computer users could face problems if a reliable exploit approach for null pointer de-referencing can be harnessed.
Organisations and home users will need to be on alert as their infrastructure is already under constant threat, particularly when the affected software is as pervasive as Adobe's Flash.