CVE-2021-26409

SNP memory corruption via unchecked RMP bounds

Published Jan 10, 2023 · Updated Apr 9, 2025

Memory corruption in SEV-ES on 3rd Gen AMD EPYC processors allows local users to corrupt the RMP and undermine SNP memory integrity. The affected SEV-ES path fails to constrain a memory operation to the Reverse Map Table's bounds, permitting corruption of protected SNP metadata. Exploitation requires local low-privileged access; AMD has not disclosed the affected function or input.

CVSS severity7.8
High
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in SEV-ES on 3rd Gen AMD EPYC processors allows local users to corrupt the RMP and undermine SNP memory integrity. The affected SEV-ES path fails to constrain a memory operation to the Reverse Map Table's bounds, permitting corruption of protected SNP metadata. Exploitation requires local low-privileged access; AMD has not disclosed the affected function or input.

The record

CVE
CVE-2021-26409
Published
Jan 10, 2023
Updated
Apr 9, 2025
Vendor
Advanced Micro Devices, Inc.
Product
3rd Gen AMD EPYC Processors
Classifications
CWE-120
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 10, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 9, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=various

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Advanced Micro Devices, Inc. · 3rd Gen AMD EPYC Processorsversion=various

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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