AMD SEV firmware - improper initialization corrupting RMP-covered memory: An initialization defect in SEV firmware lets

CVSS 5.9CVE-2025-29952Firmware, BMC & network fabriccurated

Impact

An initialization defect in SEV firmware lets an admin-privileged attacker corrupt memory covered by the RMP, costing confidential guest integrity. Same family as the other RMP issues in this batch and shipped in the same AMD advisory wave - the recurring theme is that SNP's protections are only as good as the firmware that sets them up.

Who can reach it

Local, admin-privileged.

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

https://nvd.nist.gov/vuln/detail/CVE-2025-29952 https://www.amd.com/en/resources/product-security.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.