CVE-2021-26397

Local memory corruption via insufficient address validation

Published May 9, 2023 · Updated Jan 28, 2025

Insufficient address validation in 3rd Gen AMD EPYC Processors before MilanPI 1.0.0.9 allows local users to corrupt sensitive memory. The AGESA flaw fails to validate an address supplied through a compromised ABL and UApp before accessing protected memory. Control of both firmware components is required, and successful corruption can damage integrity or interrupt platform availability.

CVSS severity7.1
High
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficient address validation in 3rd Gen AMD EPYC Processors before MilanPI 1.0.0.9 allows local users to corrupt sensitive memory. The AGESA flaw fails to validate an address supplied through a compromised ABL and UApp before accessing protected memory. Control of both firmware components is required, and successful corruption can damage integrity or interrupt platform availability.

The record

CVE
CVE-2021-26397
Published
May 9, 2023
Updated
Jan 28, 2025
Vendor
Advanced Micro Devices, Inc.
Product
3rd Gen AMD EPYC Processors
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. May 9, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 28, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=various

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

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

Published CVSS scores

7.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
7.1CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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.

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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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