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: EmbGenoaPI-SP5 1.0.0.D |
2026-02-02 | |
| 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: EmbGenoaPI-SP5 1.0.0.D |
2026-02-02 | |
| AMD EPYC™ Embedded 9004 Series Processors (Bergamo) | Option 1: Bergamo:0x0AA0021B |
2025-10-31 |
| Option 2: EmbGenoaPI-SP5 1.0.0.D |
2026-02-02 | |
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 |
| 2026-02-23 | Updated mitigations |
| 2026-01-15 | Initial publication |
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