CVE-2021-33626

mediumpriority · track · 31EPSS 0.003 · 23 %ileDEEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.31% (23rd) EPSS

CVSS 4.6 · medium

Is it mine?

60 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · siemens_psirt

EPSS · scored 2026-10-27

A vulnerability exists in SMM (System Management Mode) branch that registers a SWSMI handler that does not sufficiently check or validate the allocated buffer pointer(QWORD values for CommBuffer). This can be used by an attacker to corrupt data in SMRAM memory and even lead to arbitrary code execution.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

FixedRUGGEDCOM APE1808 - BIOSsiemens_psirt
Update to V1.0.202N or later version
https://support.industry.siemens.com/cs/ww/en/view/109814796/
FixedSIMATIC Field PG M5siemens_psirt
Update to V22.01.10 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIMATIC Field PG M6siemens_psirt
Update to V26.01.13 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIMATIC IPC127Esiemens_psirt
Update to V27.01.09 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIMATIC IPC227Gsiemens_psirt
Update to V28.01.04 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIMATIC IPC277Gsiemens_psirt
Update to V28.01.04 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIMATIC IPC327Gsiemens_psirt
Update to V28.01.04 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIMATIC IPC377Gsiemens_psirt
Update to V28.01.04 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIMATIC IPC427Esiemens_psirt
Update to V21.01.17 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIMATIC IPC477Esiemens_psirt
Update to V21.01.17 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIMATIC IPC477E Prosiemens_psirt
Update to V21.01.17 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIMATIC IPC627Esiemens_psirt
Update to V25.02.12 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIMATIC IPC647Esiemens_psirt
Update to V25.02.12 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIMATIC IPC677Esiemens_psirt
Update to V25.02.12 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIMATIC IPC847Esiemens_psirt
Update to V25.02.12 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIMATIC ITP1000siemens_psirt
Update to V23.01.10 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIMATIC IPC277G PROsiemens_psirt
Update to V28.01.04 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
FixedSIPLUS IPC427Esiemens_psirt
Update to V21.01.17 or later version
https://support.industry.siemens.com/cs/ww/en/view/109763408/
MitigationRUGGEDCOM APE1808 - BIOSsiemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC Field PG M5siemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC Field PG M6siemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC IPC127Esiemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC IPC227Gsiemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC IPC277Gsiemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC IPC327Gsiemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC IPC377Gsiemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC IPC427Esiemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC IPC477Esiemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC IPC477E Prosiemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC IPC627Esiemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC IPC647Esiemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC IPC677Esiemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC IPC847Esiemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC ITP1000siemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIMATIC IPC277G PROsiemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code
MitigationSIPLUS IPC427Esiemens_psirt
As a prerequisite for an attack, an attacker must be able to run untrusted code on affected systems. Siemens recommends limiting the possibilities to run untrusted code

cvss

Technical severity, 0–10. One row per scoring source.

7.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.6–7.8

v2.04.6mediumAV:L/AC:L/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 3.9 · impact 6.4

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 1.8 · impact 5.9

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · Siemens ProductCERT DE

v3.17.1highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-829USprimaryCWE-829US

affected products (60)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
insyde insydeh2o5.1 → 5.16.25nvdUScpe:2.3:o:insyde:insydeh2o:*:*:*:*:*:*:*:*
insyde insydeh2o5.2 → 5.25.44nvdUScpe:2.3:o:insyde:insydeh2o:*:*:*:*:*:*:*:*
insyde insydeh2o5.2 → 5.26.25nvdUScpe:2.3:o:insyde:insydeh2o:*:*:*:*:*:*:*:*
insyde insydeh2o5.3 → 5.34.44nvdUScpe:2.3:o:insyde:insydeh2o:*:*:*:*:*:*:*:*
insyde insydeh2o5.3 → 5.35.25nvdUScpe:2.3:o:insyde:insydeh2o:*:*:*:*:*:*:*:*
insyde insydeh2o5.4 → 5.42.44nvdUScpe:2.3:o:insyde:insydeh2o:*:*:*:*:*:*:*:*
insyde insydeh2o5.4 → 5.43.25nvdUScpe:2.3:o:insyde:insydeh2o:*:*:*:*:*:*:*:*
siemens ruggedcom apr1808 firmwareall versionsnvdUScpe:2.3:o:siemens:ruggedcom_apr1808_firmware:*:*:*:*:*:*:*:*
siemens simatic field pg m5 firmwareall versionsnvdUScpe:2.3:o:siemens:simatic_field_pg_m5_firmware:*:*:*:*:*:*:*:*
siemens simatic field pg m6 firmwareall versionsnvdUScpe:2.3:o:siemens:simatic_field_pg_m6_firmware:*:*:*:*:*:*:*:*
siemens simatic ipc127e firmwareall versionsnvdUScpe:2.3:o:siemens:simatic_ipc127e_firmware:*:*:*:*:*:*:*:*
siemens simatic ipc227g firmwareall versionsnvdUScpe:2.3:o:siemens:simatic_ipc227g_firmware:*:*:*:*:*:*:*:*
siemens simatic ipc277g firmwareall versionsnvdUScpe:2.3:o:siemens:simatic_ipc277g_firmware:*:*:*:*:*:*:*:*
siemens simatic ipc327g firmwareall versionsnvdUScpe:2.3:o:siemens:simatic_ipc327g_firmware:*:*:*:*:*:*:*:*
siemens simatic ipc377g firmwareall versionsnvdUScpe:2.3:o:siemens:simatic_ipc377g_firmware:*:*:*:*:*:*:*:*
siemens simatic ipc427e firmwareall versionsnvdUScpe:2.3:o:siemens:simatic_ipc427e_firmware:*:*:*:*:*:*:*:*
siemens simatic ipc477e firmwareall versionsnvdUScpe:2.3:o:siemens:simatic_ipc477e_firmware:*:*:*:*:*:*:*:*
siemens simatic ipc477e pro firmwareall versionsnvdUScpe:2.3:o:siemens:simatic_ipc477e_pro_firmware:*:*:*:*:*:*:*:*
siemens simatic ipc627e firmwareall versionsnvdUScpe:2.3:o:siemens:simatic_ipc627e_firmware:*:*:*:*:*:*:*:*

showing 20 of 60

advisories (1)

Vendor and ecosystem advisories describing this.

SSA-306654SSA-306654: Insyde BIOS Vulnerabilities in Siemens Industrial Products2022-02-22csaf · siemens_psirtDE
Insyde has published information on vulnerabilities in Insyde BIOS in February 2022. This advisory lists the Siemens Industrial products affected by these vulnerabilities. Siemens has released new versions for the affected products and recommends to update to the latest versions.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd siemens_psirt NVD CVE.org MITRE

published 2021-10-01modified 2026-08-11

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references (17)

External citations — patches, advisories, analysis.

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