CVE-2021-26338Network attack vector

Resource exhaustion via unauthorized performance-table overwrite

Published Nov 16, 2021 · Updated Sep 17, 2024

Improper access control in AMD EPYC SMU firmware allows remote attackers to exhaust resources by overwriting DRAM performance tables. The SMU accepts an unauthorized write that replaces its performance-control table contents in DRAM. No user interaction or prior authentication is required in NVD's assessment; the bounded consequence is reduced resource availability.

CVSS severity7.5
High
EPSS probability0.93%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in AMD EPYC SMU firmware allows remote attackers to exhaust resources by overwriting DRAM performance tables. The SMU accepts an unauthorized write that replaces its performance-control table contents in DRAM. No user interaction or prior authentication is required in NVD's assessment; the bounded consequence is reduced resource availability.

The record

CVE
CVE-2021-26338
Published
Nov 16, 2021
Updated
Sep 17, 2024
Vendor
Advanced Micro Devices, Inc.
Product
3rd Gen AMD EPYC Processors
Classifications
CWE-284, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 16, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record 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=unspecified <MilanPI-SP3_1.0.0.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Advanced Micro Devices, Inc. · 3rd Gen AMD EPYC Processorsversion=unspecified <MilanPI-SP3_1.0.0.4
Advanced Micro Devices, Inc. · 2nd Gen AMD EPYC Processorsversion=unspecified <RomePI-SP3_1.0.0.C

Published CVSS scores

7.8NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:C
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1499.004Application or System Exploitation

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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