New 'GeForge' and 'GDDRHammer' Rowhammer attacks compromise GPU VRAM to gain system memory access

Two new Rowhammer attacks, GDDRHammer and GeForge, target GDDR6 VRAM on Nvidia GPUs to induce bit flips and break GPU memory isolation.

Attackers use memory massaging to steer sensitive GPU data structures and corrupt page tables or the page directory, enabling read/write access to VRAM and mapped CPU memory.

Researchers observed up to 1,171 bit flips on an RTX 3060 and confirmed vulnerabilities in most of 25 tested GDDR6 GPUs.

Enabling IOMMU in BIOS or using ECC are recommended mitigations, though ECC reduces usable VRAM and IOMMU is disabled by default on many systems.