CVE-2021-26378

Service interruption via unchecked SMU address access

Published May 11, 2022 · Updated Sep 16, 2024

Out-of-bounds access in affected AMD EPYC and Ryzen processor SMUs allows local users to interrupt service via PCIe hot-plug data. SMU processing for hot-plug PCIe ports fails to reject out-of-range data before accessing or updating an invalid address space. Local low-privilege execution is required, and the documented consequence is availability loss without reported data disclosure or modification.

CVSS severity5.5
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in affected AMD EPYC and Ryzen processor SMUs allows local users to interrupt service via PCIe hot-plug data. SMU processing for hot-plug PCIe ports fails to reject out-of-range data before accessing or updating an invalid address space. Local low-privilege execution is required, and the documented consequence is availability loss without reported data disclosure or modification.

The record

CVE
CVE-2021-26378
Published
May 11, 2022
Updated
Sep 16, 2024
Vendor
AMD
Product
AMD EPYC Processors
Classifications
CWE-119, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 11, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=various

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

AMD · AMD EPYC Processorsversion=various
AMD · AMD Athlon Processorsversion=various
AMD · AMD Ryzen Processorsversion=various

Published CVSS scores

4.9NIST NVDAV:L/AC:L/Au:N/C:N/I:N/A:C
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
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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