CVE-2023-31355

Decommissioned guest memory disclosure via UMC seed overwrite

Published Aug 5, 2024 · Updated Aug 6, 2024

Information disclosure in AMD SEV-SNP firmware on affected EPYC processors allows malicious hypervisors to read decommissioned guest memory. The firmware insufficiently restricts writes to a guest's UMC seed, allowing a host-controlled hypervisor to overwrite that seed and access residual guest memory. Exploitation requires control of the host hypervisor and affects confidentiality without a reported integrity or availability impact.

CVSS severity6.0
Medium
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Information disclosure in AMD SEV-SNP firmware on affected EPYC processors allows malicious hypervisors to read decommissioned guest memory. The firmware insufficiently restricts writes to a guest's UMC seed, allowing a host-controlled hypervisor to overwrite that seed and access residual guest memory. Exploitation requires control of the host hypervisor and affects confidentiality without a reported integrity or availability impact.

The record

CVE
CVE-2023-31355
Published
Aug 5, 2024
Updated
Aug 6, 2024
Vendor
Advanced Micro Devices, Inc.
Product
AMD EPYC Embedded 7003 Series Processors
Classifications
CWE-119, CWE-787, T1005
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Aug 5, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 6, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=various <EmbMilanPI-SP3 1.0.0.9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Advanced Micro Devices, Inc. · AMD EPYC Embedded 7003 Series Processorsversion=various <EmbMilanPI-SP3 1.0.0.9
Advanced Micro Devices, Inc. · AMD EPYC Embedded 9003 Series Processorsversion=various <EmbGenoaPI-SP5 1.0.0.7
Advanced Micro Devices, Inc. · 4th Gen AMD EPYC Processorsversion=various <GenoaPI 1.0.0.C
Advanced Micro Devices, Inc. · AMD EPYC™ 7003 Series Processorsversion=various <MilanPI 1.0.0.D

Published CVSS scores

6.0Advanced Micro Devices, Inc.CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N
6.0NISTCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-787Out-of-bounds Write
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo