AMD EPYC SEV-SNP: Improper input validation allows MMIO overlap with DRAM
Summary
AMD Secure Encrypted Virtualization - Secure Nested Paging (SEV-SNP) on several AMD EPYC and EPYC Embedded processor series does not properly check unusual or exceptional conditions. A privileged local attacker can map MMIO regions over DRAM regions, which can lead to a loss of integrity. The issue is relevant only to hosts that run SEV-SNP confidential virtual machines, and the attacker must already hold high privileges on the host.
Affected
- AMD EPYC 9004, 7003, 9005, 8004 and 8005 series processors (per the CVE record, default affected)
- AMD EPYC Embedded 7003, 8004, 9004 and 9005 series processors (per the CVE record, default affected)
- Exact affected firmware versions: Unknown. Sources conflict; verify against AMD-SB-3038.
Fixed in
Unknown.
Workaround
Unknown.
Exploitation
- No public proof of concept confirmed at this time.
- Not listed as known exploited (OffSeq: Not known to be exploited). Not verified in the CISA KEV catalogue.
Our recommendation
- Add AMD-SB-3038 to the patch list for EPYC hosts that run SEV-SNP workloads.
- Check with your server or BIOS vendor for firmware updates addressing this CVE and apply them once confirmed.
- Restrict administrative access to hypervisors and hosts, since the attack requires high privileges.
- Monitor the NVD and AMD advisories for the fixed versions and any analysis update.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- AMD Security Bulletin AMD-SB-3038 www.amd.com
- AMD Product Security www.amd.com
- Strix CVE-2026-40670 www.strix.ai
- ThreatIntel CVE-2026-40670 cve.threatint.com
- OffSeq Radar CVE-2026-40670 radar.offseq.com
- Supermicro Security Center www.supermicro.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 14:56.
Original description (NVD)
Improper check for unusual or exceptional conditions in AMD Secure Encrypted Virtualization - Secure Nested Paging (SEV-SNP) could allow a privileged attacker to potentially overlap MMIO regions with DRAM regions resulting in loss of integrity.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
Affected? We can help.
We check whether your systems are affected, install updates and close the gap – continuously with the System Health Checker if you wish.