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Saint RMPocalypse, Brought Down by Eight Bytes
Patron of confidential virtual machines, clouds that swear they cannot look, and tables protected a moment too late.
Life
In October 2025 Benedict Schlüter and Shweta Shinde of ETH Zurich showed that AMD SEV-SNP, the technology that shields confidential VMs even from the hypervisor, had a weak spot at birth. While the Reverse Map Table, which holds the permissions for all of memory, was being initialised, a malicious hypervisor could leave dirty cache lines destined to land inside it: eight bytes were enough to control the whole table, forge attestation and read VM memory, on Zen 3, 4 and 5.
Prayer
O Saint RMPocalypse, who toppled the temple with eight bytes, let our tables be protected from the very first instant. Amen.
How to celebrate
Celebrated by updating AMD firmware for SEV-SNP and distrusting anyone who promises the cloud cannot look.
Small crack, great collapse.