In 2015, researchers reported a surprising discovery that stoked industry-wide security concerns—an attack called RowHammer that could corrupt, modify, or steal sensitive data when a simple user-level application repeatedly accessed certain regions of DDR memory chips. In the coming years, memory chipmakers scrambled to develop defenses that prevented the attack, mainly by limiting the number of times programs could open and close the targeted chip regions in a given time.

Source: Technology Lab – Ars Technica