CVE-2021-39298

Privileged firmware code execution through SMM access

Published Feb 16, 2022 · Updated Aug 4, 2024

Arbitrary code execution in AMD processor UEFI firmware allows attackers with high privileges to gain System Management Mode access. The flaw is in the SMM interrupt handler, but AMD has not disclosed the handler operation or input validation failure that permits entry. Successful exploitation requires existing high privileges and permits code to run in SMM, bypassing security mechanisms enforced by the affected firmware.

CVSS severity8.8
High
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Arbitrary code execution in AMD processor UEFI firmware allows attackers with high privileges to gain System Management Mode access. The flaw is in the SMM interrupt handler, but AMD has not disclosed the handler operation or input validation failure that permits entry. Successful exploitation requires existing high privileges and permits code to run in SMM, bypassing security mechanisms enforced by the affected firmware.

The record

CVE
CVE-2021-39298
Published
Feb 16, 2022
Updated
Aug 4, 2024
Vendor
AMD
Product
2nd Gen AMD EPYC Processors
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 16, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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 · 2nd Gen AMD EPYC Processorsversion=Various
AMD · AMD Ryzen 2000 Series Processorsversion=various
AMD · AMD Ryzen 5000 Series Processorsversion=various
AMD · AMD Ryzen 3000 Series Processorsversion=Various
AMD · 3rd Gen AMD EPYC Processorsversion=various

Published CVSS scores

7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
8.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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

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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