AMD Chip Flaw: VMs Exposed by StackWarp Vulnerability

A newly identified hardware vulnerability, dubbed StackWarp, affects AMD processors from Zen 1 through 5. Researchers revealed that this flaw can undermine the security of confidential virtual machines by manipulating processor stack tracking. This manipulation enables attackers with privileged host access to achieve remote code execution and escalate privileges within a protected virtual machine environment. Consequently, sensitive data, such as private keys, could be compromised, and system integrity jeopardized.

The exploit requires attackers to first gain control over the host server running the virtual machines. This prerequisite narrows the potential threat actors to malicious insiders, cloud providers, or advanced persistent threats. Despite this limitation, the vulnerability demonstrates a weakness in AMD's SEV-SNP technology, which is designed to encrypt VM memory and ensure execution integrity. The researchers successfully reconstructed private keys and bypassed authentication mechanisms in their demonstrations.

AMD has acknowledged the findings and has issued a patch to mitigate the StackWarp vulnerability. The issue is now officially tracked as CVE-2025-29943 and has been assigned a low severity score of 3.2 out of 10. While the impact is considered low due to the access requirements, the discovery highlights ongoing challenges in securing virtualized environments.