SEV-SNP Guest Stack Pointer Corruption Vulnerability

Summary

Researchers have reported a CPU-caused stack corruption issue caused by flipping an undocumented MSR bit.

AMD believes that this vulnerability occurs due to inadequate access controls, which fail to prevent the hypervisor from setting  an internal configuration bit. This attack could allow a malicious hypervisor to manipulate the configuration of the CPU pipeline, potentially resulting in corruption of the stack pointer inside an SEV-SNP guest running on the sibling (Simultaneous Multithreading) SMT thread. AMD has released mitigations for this vulnerability.

CVE Details

CVE

CVE Description

CVSS Score

CVE-2025-29943

 

Improper access control within AMD CPUs may allow an admin-privileged attacker to modify the configuration of the CPU pipeline, potentially resulting in the corruption of the stack pointer inside an SEV-SNP guest.

3.2 (Low)
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:L/A:N

4.6 (Medium)
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

Affected Products and Mitigation

AMD recommends updating to the Platform Initialization (PI) firmware version indicated below (note the PI firmware versions were released by AMD to the Original Equipment Manufacturers (OEM) on the dates listed below). Please contact your OEM for the BIOS update specific to your product(s).

AMD EPYC™ Processors

Product

Former Codename

Mitigation
Option 1: µcode

Option 2: AGESA/PI

Release Date

AMD EPYC™ 4004 Series Processors

"Raphael"

Not affected

AMD EPYC™ 7001 Series Processors

"Naples"

Not affected

AMD EPYC™ 7002 Series Processors

"Rome"

Not affected

AMD EPYC™ 7003 Series Processors

“Milan”

“Milan-X”

Milan B1:0x0A0011DE
Milan-X:0x0A001247

 OR

MilanPI 1.0.0.H

µcode standalone release: 2025-07-14

AGESA Release 2025-09-04

AMD EPYC™ 8004 Series Processors

“Siena”

Genoa:0x0A101156
Genoa-X: 0x0A101251
Bergamo/Sienna A2: 0x0AA0021B

OR

GenoaPI 1.0.0.H

µcode standalone release: 2025-07-14

AGESA Release 2025-12-15

AMD EPYC™ 9004 Series Processors

“Genoa”

“Genoa-X”

“Bergamo”

AMD EPYC™ 9005 Series Processors

"Turin"

“Turin Dense”

Turin C1: 0x0B002151
Turin Dense B0: 0x0B10104E

OR

TurinPI 1.0.0.6

µcode standalone release: 2025-07-14

AGESA Release: 2025-06-30

AMD EPYC™ 9V64H Processor

Not affected

AMD EPYC™ Embedded Processors

Product

Mitigation
Option 1: µcode OR
Option 2: AGESA

Release Date

AMD EPYC™ Embedded 3000 Series Processors

Not affected

AMD EPYC™ Embedded 7002 Series Processors

Not affected

AMD EPYC™ Embedded 7003 Series Processors

EmbMilanPI-SP3 v9 1.0.0.C

2025-10-31

AMD EPYC™ Embedded 8004 Series Processors

Option 1:

Siena A2: 0x0AA0021B

2025-10-31

Option 2:

Version TBD

Target release Apr’26

AMD EPYC™ Embedded 9005 Series Processors

EmbTurinPI-SP5_1.0.0.1

2025-10-31

AMD EPYC™ Embedded 9004 Series Processors (Genoa)

Option 1:

Genoa B1:0x0A101156
Genoa B2:0x0A101251

2025-10-31

Option 2:

Version TBD

Target release Apr’26

AMD EPYC™ Embedded 9004 Series Processors (Bergamo)

Option 1:

Bergamo: 0x0AA0021B

2025-10-31

Option 2:

Version TBD

Target release Apr’26

Acknowledgement 

AMD thanks Ruiyi Zhang, Tristan Hornetz, Daniel Weber, Fabian Thomas, Lukas Gerlach, and Michael Schwarz of CISPA, Youheng Lü of SCHUTZWERK GmbH for reporting this issue and engaging in coordinated vulnerability disclosure. 

Revisions 

Revision Date  

Description  

2026-01-15

Initial publication

DISCLAIMER

The information contained herein is for informational purposes only and is subject to change without notice. While every precaution has been taken in the preparation of this document, it may contain technical inaccuracies, omissions and typographical errors, and AMD is under no obligation to update or otherwise correct this information. Advanced Micro Devices, Inc. makes no representations or warranties with respect to the accuracy or completeness of the contents of this document, and assumes no liability of any kind, including the implied warranties of noninfringement, merchantability or fitness for particular purposes, with respect to the operation or use of AMD hardware, software or other products described herein. Any computer system has risks of security vulnerabilities that cannot be completely prevented or mitigated. No license, including implied or arising by estoppel, to any intellectual property rights is granted by this document. Terms and limitations applicable to the purchase or use of AMD’s products are as set forth in a signed agreement between the parties or in AMD's Standard Terms and Conditions of Sale.

AMD, the AMD Arrow logo, EPYC, and combinations thereof are trademarks of Advanced Micro Devices, Inc. CVE and the CVE logo are registered trademarks of The MITRE Corporation. Other product names used in this publication are for identification purposes only and may be trademarks of their respective companies.

Third party content may be licensed to you directly by the third party that owns the content and is not licensed to you by AMD. ALL LINKED THIRD-PARTY CONTENT IS PROVIDED ‘AS IS’ WITHOUT A WARRANTY OF ANY KIND. USE OF SUCH THIRD-PARTY CONTENT IS DONE AT YOUR SOLE DISCRETION AND UNDER NO CIRCUMSTANCES WILL AMD BE LIABLE TO YOU FOR ANY THIRD PARTY CONTENT. YOU ASSUME ALL RISK AND ARE SOLELY RESPONSIBILITY FOR ANY DAMAGES THAT MAY ARISE FROM YOUR USE OF THIRD-PARTY CONTENT.

© 2026 Advanced Micro Devices, Inc. All rights reserved.