CVE-2021-26353

Memory corruption via partially initialized DRTM UApp

Published May 10, 2022 · Updated Aug 3, 2024

Improper initialization in AMD 3rd Gen EPYC processors allows local users to corrupt memory through crafted SMM inputs. The SMM path mishandles invalid input, leaving the DRTM UApp partially initialized so later mailbox commands perform unchecked memory writes. Low-privileged local access is required, and the bounded consequence is loss of memory integrity.

CVSS severity7.8
High
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper initialization in AMD 3rd Gen EPYC processors allows local users to corrupt memory through crafted SMM inputs. The SMM path mishandles invalid input, leaving the DRTM UApp partially initialized so later mailbox commands perform unchecked memory writes. Low-privileged local access is required, and the bounded consequence is loss of memory integrity.

The record

CVE
CVE-2021-26353
Published
May 10, 2022
Updated
Aug 3, 2024
Vendor
Advanced Micro Devices, Inc.
Product
3rd Gen AMD EPYC Processors
Classifications
CWE-665
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 10, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

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

Published CVSS scores

7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
7.8NIST NVDCVSS: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-665Improper Initialization

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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