CVE-2021-26334

Local privilege escalation via unrestricted MSR access

Published Dec 1, 2021 · Updated Sep 17, 2024

Improper access control in AMD μProf before 3.4.494 allows local users to execute ring-0 code through AMDPowerProfiler.sys. The driver exposes model-specific register access to lower-privileged processes instead of restricting that kernel operation. Local access to an affected installation is required, and successful abuse grants kernel-level execution.

CVSS severity9.9
Critical
EPSS probability1.17%
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 μProf before 3.4.494 allows local users to execute ring-0 code through AMDPowerProfiler.sys. The driver exposes model-specific register access to lower-privileged processes instead of restricting that kernel operation. Local access to an affected installation is required, and successful abuse grants kernel-level execution.

The record

CVE
CVE-2021-26334
Published
Dec 1, 2021
Updated
Sep 17, 2024
Vendor
Advanced Micro Devices, Inc.
Product
AMD μProf Tool
Classifications
CWE-284, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 1, 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=μProf Tool <3.4.494

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Advanced Micro Devices, Inc. · AMD μProf Toolversion=μProf Tool <3.4.494

Published CVSS scores

9.9NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
9.0NIST NVDAV:N/AC:L/Au:S/C:C/I:C/A:C

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-284Improper Access Control
T1068Exploitation for Privilege Escalation

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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