CVE-2021-26344

Arbitrary code execution via signed APCB corruption

Published Aug 13, 2024 · Updated Mar 18, 2025

Out-of-bounds write in AMD PSP1 APCB processing allows local users to execute arbitrary code through a modified, signed BIOS image. The PSP1 firmware writes beyond the APCB buffer while processing attacker-controlled configuration data embedded in the BIOS image. Exploitation requires high privileges, user interaction, BIOS-image modification, and a valid signature, and successful execution can compromise platform confidentiality, integrity, and availability.

CVSS severity7.2
High
EPSS probability0.16%
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 write in AMD PSP1 APCB processing allows local users to execute arbitrary code through a modified, signed BIOS image. The PSP1 firmware writes beyond the APCB buffer while processing attacker-controlled configuration data embedded in the BIOS image. Exploitation requires high privileges, user interaction, BIOS-image modification, and a valid signature, and successful execution can compromise platform confidentiality, integrity, and availability.

The record

CVE
CVE-2021-26344
Published
Aug 13, 2024
Updated
Mar 18, 2025
Vendor
Advanced Micro Devices, Inc.
Product
AMD Ryzen™ Embedded V1000 Series Processors
Classifications
CWE-787, T1542.001
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Aug 13, 2024CVE publishedPublication date reported by the CVE source.
  2. Mar 18, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=v

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Advanced Micro Devices, Inc. · AMD Ryzen™ Embedded V1000 Series Processorsversion=v
Advanced Micro Devices, Inc. · AMD Ryzen™ 3000 Series Processors with Radeon™ GraphicsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen Threadripper PRO 5000WX ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD RomePIversion=0 <1.0.0.C
Advanced Micro Devices, Inc. · AMD Athlon™ 3000 Series Desktop Processors with Radeon™ Graphicsversion=various
Advanced Micro Devices, Inc. · AMD Ryzen™ 3000 Series Mobile Processors with Radeon™ Graphicsversion=various
Advanced Micro Devices, Inc. · AMD MilanPIversion=0 <1.0.0.5
Advanced Micro Devices, Inc. · AMD Ryzen™ Embedded R2000 Series Processorsversion=v
Advanced Micro Devices, Inc. · AMD EPYC Embedded 7003 Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD EPYC Embedded 7002 Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Athlon™ 3000 Series Mobile Processors with Radeon™ Graphicsversion=various
Advanced Micro Devices, Inc. · AMD Ryzen™ Embedded V3000 Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen™ Threadripper™ 3000 Series Processorsversion=various
Advanced Micro Devices, Inc. · AMD Ryzen Embedded V2000 Series Processorsversion=v
Advanced Micro Devices, Inc. · AMD EPYC Embedded 3000 Series Processorsversion=Various
Advanced Micro Devices, Inc. · AMD Ryzen™ Embedded 5000 Series Processorsversion=v
Advanced Micro Devices, Inc. · AMD Ryzen™ 5000 Series Mobile Processors with Radeon™ Graphicsversion=various
Advanced Micro Devices, Inc. · AMD Ryzen™ 6000 Series Processors with Radeon™ GraphicsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen™ 4000 Series Desktop Processors with Radeon™ Graphicsversion=various
Advanced Micro Devices, Inc. · AMD EPYC™ 7001 Series Processorsversion=various
Advanced Micro Devices, Inc. · AMD Ryzen™ 7035 Series Processors with Radeon™ GraphicsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD EPYC 7002 Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen™ 7020 Series Processors with Radeon™ GraphicsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen™ Embedded R1000 Series Processorsversion=v
Advanced Micro Devices, Inc. · AMD Ryzen™ 3000 Series Desktop Processorsversion=various
Advanced Micro Devices, Inc. · AMD Ryzen™ 5000 Series Desktop ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD NaplesPIversion=0 <1.0.0.k
Advanced Micro Devices, Inc. · AMD Ryzen™ 5000 Series Processors with Radeon™ GraphicsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen™ 5000 Series Desktop Processor with Radeon™ GraphicsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD EPYC™ 7003 Series ProcessorsAffected versions are unavailable in this record.
Advanced Micro Devices, Inc. · AMD Ryzen™ 4000 Series Mobile Processors with Radeon™ Graphicsversion=various

Published CVSS scores

8.2NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
7.2Advanced Micro Devices, Inc.CVSS:3.1/AV:L/AC:H/PR:H/UI:R/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.

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1542.001Pre-OS Boot: System Firmware

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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