An attacker with access to a malicious hypervisor may be able to infer data values used in a SEV guest on AMD CPUs by monitoring ciphertext values over time.

AMD EPYC™ Processors contain an information disclosure vulnerability in the Secure Encrypted Virtualization with Encrypted State (SEV-ES) and Secure Encrypted Virtualization with Secure Nested Paging (SEV-SNP). A local authenticated attacker could potentially exploit this vulnerability leading to leaking guest data by the malicious hypervisor.

A malicious hypervisor in conjunction with an unprivileged attacker process inside an SEV/SEV-ES guest VM may fail to flush the Translation Lookaside Buffer (TLB) resulting in unexpected behavior inside the virtual machine (VM).

The lack of nested page table protection in the AMD SEV/SEV-ES feature could potentially lead to arbitrary code execution within the guest VM if a malicious administrator has access to compromise the server hypervisor.