GPUThor researchers report host-root route on vulnerable Nvidia workstation GPUs

University of Toronto researchers disclosed GPUThor, a Rowhammer attack they report can induce multi-bit errors on four Nvidia Ampere workstation GPUs with GDDR6 memory and use them for denial of service or host-side privilege escalation. The attack requires an unprivileged CUDA kernel on the target GPU, including from a co-tenant on a shared card. On a locally owned RTX A6000 with ECC enabled, the researchers reported detectable uncorrectable errors and one silent data-corruption event over a day. Nvidia guidance says System-Level ECC mitigates the Rowhammer problem.