A security researcher reported a flaw in VMRUN error handling that may expose Secure Encrypted Virtualization -Secure Nested Paging (SEV-SNP) guest register data to a privileged attacker via a Transient Scheduler Attacks (TSA) side channel attack resulting in a loss of confidentiality. AMD has assessed the report and plans to release mitigations.
Refer to Glossary for explanation of terms
Incomplete cleanup during VMRUN error handling could allow access to a Secure Encrypted Virtualization-Secure Nested Paging (SEV-SNP) guest register state, potentially resulting in information disclosure and impacts to confidentiality.
4.9 CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N CWE- 459: Incomplete Cleanup
Specific CVSS scores may change subject to your implementation. We encourage you to calculate CVSS scores independently for your system.
Affected Products and Mitigation
AMD plans to release to the Original Equipment Manufacturers (OEM) the Platform Initialization (PI) firmware versions on the target dates listed below. Please your OEM for the BIOS update specific to your product(s).
*Note: Products believed to not be affected by the listed CVEs are not included.AMD EPYC™ Series Processors
AMD EPYC™ Series Processors
Platform Initialization (PI) Mitigation
Microcode Release Date
AMD EPYC™ 7003 Series Processors
Target release planned for Nov'26
AMD EPYC™ 8004 Series Processors
Target release planned for Nov'26
AMD EPYC™ 8005 Series Processors
Target release planned for Nov'26
AMD EPYC™ 9004 Series Processors
Target release planned for Nov'26
Genoa RS-B1 0x0A10115B
Genoa-RS-B2 0x0A10125B
AMD EPYC™ 9005 Series Processors
Target release planned for Nov'26
Turin Classic -BRH C1 0x0B002176
Turin Dense - BRH D B0 0x0B101067
AMD Instinct™ Accelerators
Platform Initialization (PI) Mitigation
Microcode Release Date
AMD Instinct™ MI300A Series Processors
Patch version 0x0A900110
AMD EPYC™ Embedded Series Processors
Mitigation Release Date
AMD EPYC™ Embedded 7003 Series Processors
Target release planned for Jan'27
AMD EPYC™ Embedded 8004 Series Processors
Target release planned for Apr'27
AMD EPYC™ Embedded 9004 Series Processors
Target release planned for Apr'27
AMD EPYC™ Embedded 9005 Series Processors
Target release planned for Feb'27
AMD thanks the following for reporting and engaging in coordinated vulnerability disclosure:
Alessandro Vezz`u1, Benedict Schluter, Shweta Shinde ETH Zurich, Daniel Moghimi Google: CVE-2026-40671
The full story
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