AMD SEV / SEV-ES - Owner's Certificate Authority (OCA) certificate parsing: Insufficient validation when parsing OCA

Impact

Insufficient validation when parsing OCA certificates in the SEV and SEV-ES user application crashes the host. OCA certificates come from whoever owns the platform's SEV identity, so this is a malformed-input crash on the certificate path that underpins SEV ownership and attestation - a guest or tooling that supplies a bad certificate takes the machine down.

Who can reach it

Reachable by whatever supplies OCA certificates to the SEV stack, which in a managed confidential-computing service is the control plane or the tenant-facing provisioning path.

What to do

Fixed in AMD reference firmware (AGESA / PSP / SEV firmware) and delivered only as an OEM SBIOS/BIOS package - Dell, HPE, Supermicro, Lenovo and the ODMs each rebuild and requalify AMD's AGESA drop before shipping. **Expect one to six months of OEM lag**, and on end-of-support platforms expect nothing. Applying it is a drain plus full power cycle, not a driver reload. Verify by reading back the PSP/SMU firmware version afterwards rather than trusting the BIOS version string. This sits inside the SEV-SNP trust boundary, so the update moves the platform's reported TCB version: refresh VCEK certificates from AMD's KDS and update any attestation policy your tenants pin, or confidential guest launches will start failing right after the BIOS lands.

References