New GPUThor Rowhammer Defeats ECC on NVIDIA RTX A6000 to Gain Host Root Access

Summary: University of Toronto researchers disclosed GPUThor, a Rowhammer attack on NVIDIA Ampere workstation GPUs with GDDR6 memory that defeats the ECC mitigation NVIDIA recommends, inducing bit flips on all four cards tested and enabling denial-of-service and privilege escalation to a host root shell. The attack uses non-uniform hammering that activates the aggressor row far more often than decoy rows, producing 72,000 to 377,000 bit flips per gigabyte with ECC disabled, and it cut an end-to-end privilege escalation on an RTX A6000 from 21.9 hours with GPUHammer's patterns to 1.1 minutes.
Bottom line: The researchers obtained root on the host with the IOMMU enabled using a triple-bit silent data corruption, and even double-bit uncorrectable errors proved exploitable because NVIDIA GPUs service DUEs lazily, leaving a roughly 10 ms window in which corrupted data is consumed. No patch addresses the attack, the exploit code is due for public release on November 15, 2026, and the team's own conclusion is that ECC raises the bar but can no longer be treated as a sufficient defense.

Read the original at The Hacker News ↗