AMD SMM - memory corruption (AMD-SB-4003): MULTI-TENANT ISOLATION: Memory corruption reachable in System Management

Impact

MULTI-TENANT ISOLATION: Memory corruption reachable in System Management Mode. Same class as the rest of the SMM cluster - a ring-0 attacker escalates into the one execution context that no hypervisor, kernel or EDR can observe, and the foothold survives OS reinstallation.

Who can reach it

Local, ring-0 privilege required.

What to do

Fixed in AMD PI/AGESA firmware and delivered only as an OEM SBIOS package - AMD ships the PI drop to Dell, HPE, Supermicro, Lenovo and the ODMs, who each requalify before releasing BIOS. **Budget one to six months of OEM lag**, and note that several CVEs in this batch are marked 'no fix planned' on Naples (EPYC 7001) - for those the only remediation is retiring the hardware. Applying it means cordon, drain and a full power cycle per node; there is no driver reload, no live patch and no VBIOS step.

References