CVE-2021-45969

SMM code execution via unchecked communication pointer

Published Jan 5, 2022 · Updated Aug 11, 2026

Memory corruption in InsydeH2O AhciBusDxe on affected Siemens industrial systems allows local users to execute code in SMM. The registered SWSMI handler writes an eight-byte status value to CommBuffer+8 without verifying that the caller-controlled pointer lies outside SMRAM. Attackers must be able to run untrusted code on the device; successful exploitation can corrupt protected firmware memory, obtain privileges above the host kernel, and persist firmware code.

CVSS severity8.4
High
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in InsydeH2O AhciBusDxe on affected Siemens industrial systems allows local users to execute code in SMM. The registered SWSMI handler writes an eight-byte status value to CommBuffer+8 without verifying that the caller-controlled pointer lies outside SMRAM. Attackers must be able to run untrusted code on the device; successful exploitation can corrupt protected firmware memory, obtain privileges above the host kernel, and persist firmware code.

The record

CVE
CVE-2021-45969
Published
Jan 5, 2022
Updated
Aug 11, 2026
Vendor
Siemens
Product
SIMATIC IPC477E PRO
Classifications
CWE-787, T1542.001
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jan 5, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 11, 2026Record 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=0 <V21.01.17

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Siemens · SIMATIC IPC477E PROversion=0 <V21.01.17
Siemens · SIMATIC IPC847Eversion=0 <V25.02.12
Siemens · SIMATIC Field PG M5version=0 <V22.01.10
Siemens · SIMATIC IPC377Gversion=0 <V28.01.04
Siemens · RUGGEDCOM APE1808 BIOSversion=0 <V1.0.202N
Siemens · SIMATIC IPC627Eversion=0 <V25.02.12
Siemens · SIMATIC IPC277Gversion=0 <V28.01.04
Siemens · SIMATIC ITP1000version=0 <V23.01.10
Siemens · SIMATIC IPC677Eversion=0 <V25.02.12
Siemens · SIMATIC IPC127E Industrial Edge Deviceversion=0 <V27.01.09
Siemens · SIMATIC IPC427E Industrial Edge Deviceversion=0 <V21.01.17
Siemens · SIMATIC IPC477Eversion=0 <V21.01.17
Siemens · SIMATIC IPC277G PROversion=0 <V28.01.04
Siemens · SIMATIC IPC227G Industrial Edge Deviceversion=0 <V28.01.04
Siemens · SIMATIC IPC327Gversion=0 <V28.01.04
Siemens · SIMATIC IPC647Eversion=0 <V25.02.12
Siemens · SIPLUS IPC427Eversion=0 <V21.01.17
Siemens · SIMATIC Field PG M6version=0 <V26.01.13

Published CVSS scores

8.4Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.2Insyde SoftwareCVSS:3.1/AV:L/AC:L/PR:H/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.

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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