Processor vulnerability
CVE-2024-36347
The ROM microcode patch loader of Zen to Zen 5 verifies signatures weakly, so an administrator can load microcode patches AMD did not sign.
- Name
- Microcode Signature Verification
- Vulnerability
- Microcode Signature Verification
- Kind
- Other
- CVE published
- 2025-06-27 CVE record
- Advisories
- AMD-SB-7033
Researchers at Google showed that the signature check of the
processor’s microcode patch loader, which is in ROM, has a weakness
in its algorithm: with administrator privilege they loaded patches
AMD had not signed and falsified signatures. Malicious microcode
undermines the integrity of every instruction, the confidentiality
of privileged data and SMM. AMD’s fix is new microcode delivered in
platform firmware, which keeps patches from being loaded after it.What the sources say of each microarchitecture.
Affected processors
5 of the 5 microarchitectures listed are affected in all or some of their models.
| Microarchitecture | Status | Detail | Source |
|---|---|---|---|
| Zen | Some models | EPYC 7001 (Naples); Athlon 3000 mobile | amd.com |
| Zen 2 | Some models | EPYC 7002 (Rome); Ryzen 3000 desktop, 4000 and 7020; Threadripper 3000 and PRO 3000WX | amd.com |
| Zen 3 | Some models | EPYC 7003 (Milan); Ryzen 5000, 6000 and 7035; Threadripper PRO 5000WX | amd.com |
| Zen 4 | Some models | EPYC 9004 and 4004; Ryzen 7000, 7040, 7045, 8000 and 8040; Threadripper PRO 7000 WX | amd.com |
| Zen 5 | Some models | EPYC 9005 (Turin); Ryzen 9000, 9000HX and AI 300 | amd.com |
Mitigations
- Firmware: AMD's PI firmware with microcode that blocks the bad patches, through BIOS updates; for EPYC, from December 2024. Source.
Related CVEs
- CVE-2024-56161 Microcode Signature Verification: SEV-SNP
- CVE-2025-0032 Microcode Patch Loading Cleanup