AMD SEV firmware: improper access control lets a malicious hypervisor bypass RMP protections

CVSS 5.9CVE-2025-0027Firmware, BMC & network fabriccurated

Impact

A malicious or compromised hypervisor can bypass the Reverse Map Table, the structure SEV-SNP relies on to stop the host from writing guest-owned memory. That breaks SEV-SNP's integrity promise to confidential VM tenants. AMD rates the impact as loss of guest memory integrity, not confidentiality. This matters to GPU clouds that sell SEV-SNP confidential VMs on EPYC hosts, because the threat model there assumes the host operator cannot be trusted. It does not change exposure for fleets that do not use SEV-SNP.

Who can reach it

Requires control of the hypervisor (host root or a compromised host stack). Not reachable from inside a guest or from the network.

What to do

Apply the AMD SEV firmware fix listed in AMD-SB-3037 for the affected EPYC generation (7003, 8004, 9004, 9005 and the Embedded variants). The record does not give fixed versions or say how the update is delivered. Check the bulletin and your server OEM for the matching platform firmware release, and plan for host maintenance on SEV-SNP nodes.

References

https://nvd.nist.gov/vuln/detail/CVE-2025-0027 https://www.amd.com/en/resources/product-security/bulletin/AMD-SB-3037.html

This entry is curated: imported from vendor advisories with machine assistance, not yet individually verified. Confirm against your vendor's advisory before acting, and report anything wrong.