CVE-2024-21977

SEV-SNP guest integrity loss via stale microcode state

Published Sep 5, 2025 · Updated Sep 5, 2025

Incomplete cleanup in AMD processor microcode loading allows local users to weaken RDRAND entropy and undermine SEV-SNP guest integrity. The loader leaves CPU state uncleared after applying a microcode patch, causing later RDRAND output to retain degraded entropy. Exploitation requires administrator-level local access, and the resulting impact is limited to integrity for SEV-SNP guests that consume the weakened random values.

CVSS severity4.6
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incomplete cleanup in AMD processor microcode loading allows local users to weaken RDRAND entropy and undermine SEV-SNP guest integrity. The loader leaves CPU state uncleared after applying a microcode patch, causing later RDRAND output to retain degraded entropy. Exploitation requires administrator-level local access, and the resulting impact is limited to integrity for SEV-SNP guests that consume the weakened random values.

The record

CVE
CVE-2024-21977
Published
Sep 5, 2025
Updated
Sep 5, 2025
Vendor
Advanced Micro Devices, Inc.
Product
AMD Ryzen™ 7000 Series Desktop Processors
Classifications
CWE-459
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 5, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 5, 2025Record 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 Ryzen™ 7000 Series Desktop ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen™ Threadripper™ PRO 3000 WX-Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen 7040 Series Mobile Processors with Radeon GraphicsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen™ Threadripper™ PRO 5000 WX-Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD EPYC Embedded 7003 Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen™ 7045 Series Mobile Processors with Radeon™ GraphicsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen™ Embedded V3000 Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD EPYC Embedded 9004 Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen™ 7030 Series Mobile Processors with Radeon™ GraphicsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen™ Embedded 5000 Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen™ 5000 Series Mobile Processors with Radeon™ GraphicsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen Embedded 8000 Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen™ 6000 Series Processors with Radeon™ GraphicsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen Embedded 7000 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 Ryzen™ 8000 Series Desktop 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 Ryzen™ 7035 Series Processors with Radeon™ GraphicsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen™ 5000 Series Desktop ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD EPYC™ 7003 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:N/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 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-459Incomplete Cleanup

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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