CVE-2021-26337

SMU service interruption via invalid DMA address

Published Nov 16, 2021 · Updated Sep 17, 2024

Insufficient address validation in the SMU on AMD Ryzen and Athlon processors allows local users to interrupt SMU service. The SMU accepts an invalid DRAM address for a DMA read into SRAM and then stops servicing requests from other components. Low-privileged code execution is required, and the published consequence is loss of SMU service rather than code execution or data modification.

CVSS severity5.5
Medium
EPSS probability0.24%
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 the SMU on AMD Ryzen and Athlon processors allows local users to interrupt SMU service. The SMU accepts an invalid DRAM address for a DMA read into SRAM and then stops servicing requests from other components. Low-privileged code execution is required, and the published consequence is loss of SMU service rather than code execution or data modification.

The record

CVE
CVE-2021-26337
Published
Nov 16, 2021
Updated
Sep 17, 2024
Vendor
AMD
Product
AMD Ryzen Series
Classifications
T1489
Attack vector
local
Privileges
authenticated

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?

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  1. Affected versionversion=various

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

AMD · AMD Ryzen Seriesversion=various
AMD · AMD Athlon Seriesversion=various

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
2.1NIST NVDAV:L/AC:L/Au:N/C:P/I:N/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.

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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

T1489Service Stop

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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