CVE-2025-29943

SEV-SNP guest stack corruption via undocumented MSR bit

Published Jan 16, 2026 · Updated Jan 16, 2026

Improper access control in affected AMD EPYC processors allows local users to corrupt an SEV-SNP guest stack pointer. Inadequate CPU access controls let a malicious hypervisor flip an undocumented MSR bit that changes pipeline configuration on a sibling SMT thread. Administrative control of the hypervisor and a co-scheduled SEV-SNP guest are required; the demonstrated consequence is guest stack-pointer corruption.

CVSS severity4.6
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in affected AMD EPYC processors allows local users to corrupt an SEV-SNP guest stack pointer. Inadequate CPU access controls let a malicious hypervisor flip an undocumented MSR bit that changes pipeline configuration on a sibling SMT thread. Administrative control of the hypervisor and a co-scheduled SEV-SNP guest are required; the demonstrated consequence is guest stack-pointer corruption.

The record

CVE
CVE-2025-29943
Published
Jan 16, 2026
Updated
Jan 16, 2026
Vendor
Advanced Micro Devices, Inc.
Product
AMD EPYC Embedded 7003 Series Processors
Classifications
CWE-123
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jan 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 16, 2026Record 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?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Advanced Micro Devices, Inc. · AMD EPYC Embedded 7003 Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD EPYC 9005 Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD EPYC™ 8004 Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD EPYC™ 9004 Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD EPYC Embedded 9005 Series ProcessorsAffected versions are unavailable in this record.

Published CVSS scores

4.6Advanced Micro Devices Inc.CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N
3.2Advanced Micro Devices Inc.CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-123Write-what-where Condition

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

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Your stack

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