RMPocalypse: Single 8-Byte Write Shatters AMD’s SEV-SNP Confidential Computing

AMD has released fixes for RMPocalypse, a vulnerability that could undermine SEV-SNP confidential computing by allowing a single memory write to the Reverse Map Paging (RMP) table. According to ETH Zürich researchers Benedict Schlüter and Shweta Shinde, the flaw arises from incomplete protections during RMP initialization and could let a malicious hypervisor tamper with RMP content, potentially breaching SEV-SNP’s confidentiality and integrity guarantees.

AMD has assigned CVE-2025-0033 (CVSS v4 score: 5.9) to the issue, described as a race condition affecting the AMD Secure Processor during RMP initialisation, with reports that an attacker could manipulate initial RMP data and jeopardise guest memory integrity. The advisory notes affected chipsets include several AMD EPYC generations, with fixes planned for some Embedded series in November 2025.

Microsoft and Supermicro have acknowledged CVE-2025-0033, with patches and BIOS updates being pursued for affected Azure Confidential Computing workloads and related motherboard SKUs.