CVE-2021-33626

HIGH

7.8

CVSS Score

Published: October 1, 2021 at 02:21 AM UTC

Updated: August 11, 2026 at 01:28 PM UTC

35 products affected across 2 vendorsInsydeH2OSIMATIC IPC477E FirmwareSIMATIC ITP1000 Firmware

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Severity

HIGH7.8

Exploit prediction

EPSS 0.3%

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

InsydeH2O · Insyde

95%

5.1 ≤ v < 5.16.255.2 ≤ v < 5.25.445.2 ≤ v < 5.26.255.3 ≤ v < 5.34.445.3 ≤ v < 5.35.255.4 ≤ v < 5.42.445.4 ≤ v < 5.43.25

Affected range stops below 5.16.25, so it looks safe — our inference, not a vendor statement

Affected range stops below 5.25.44, so it looks safe — our inference, not a vendor statement

Affected range stops below 5.26.25, so it looks safe — our inference, not a vendor statement

Affected range stops below 5.34.44, so it looks safe — our inference, not a vendor statement

Affected range stops below 5.35.25, so it looks safe — our inference, not a vendor statement

Affected range stops below 5.42.44, so it looks safe — our inference, not a vendor statement

Affected range stops below 5.43.25, so it looks safe — our inference, not a vendor statement

RUGGEDCOM APR1808 Firmware · Siemens

95%

All versions

siemens-ruggedcom-apr1808 (same device)

SIMATIC Field Pg M5 Firmware · Siemens

95%

v < V22.01.10

Affected range stops below V22.01.10, so it looks safe — our inference, not a vendor statement

siemens-simatic-field-pg-m5 (same device)

SIMATIC Field Pg M6 Firmware · Siemens

95%

v < V26.01.13

Affected range stops below V26.01.13, so it looks safe — our inference, not a vendor statement

siemens-simatic-field-pg-m6 (same device)

SIMATIC IPC127E Firmware · Siemens

95%

All versions

siemens-simatic-ipc127e (same device)

SIMATIC IPC227G Firmware · Siemens

95%

All versions

siemens-simatic-ipc227g (same device)

SIMATIC IPC277G Firmware · Siemens

95%

v < V28.01.04

Affected range stops below V28.01.04, so it looks safe — our inference, not a vendor statement

siemens-simatic-ipc277g (same device)

SIMATIC IPC327G Firmware · Siemens

95%

v < V28.01.04

Affected range stops below V28.01.04, so it looks safe — our inference, not a vendor statement

siemens-simatic-ipc327g (same device)

SIMATIC IPC377G Firmware · Siemens

95%

v < V28.01.04

Affected range stops below V28.01.04, so it looks safe — our inference, not a vendor statement

siemens-simatic-ipc377g (same device)

SIMATIC IPC427E Firmware · Siemens

95%

All versions

siemens-simatic-ipc427e (same device)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (6)

x_refsource_CONFIRMThird Party Advisory

Source: [email protected]

https://cert-portal.siemens.com/productcert/pdf/ssa-306654.pdf

x_refsource_CONFIRMThird Party Advisory

Source: [email protected]

https://security.netapp.com/advisory/ntap-20220216-0006/

x_refsource_MISCVendor Advisory

Source: [email protected]

https://www.insyde.com/security-pledge

x_refsource_MISCVendor Advisory

Source: [email protected]

https://www.insyde.com/security-pledge/SA-2021001

Source: af854a3a-2127-422b-91ae-364da2661108

https://www.kb.cert.org/vuls/id/796611

Source: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e

https://cert-portal.siemens.com/productcert/html/ssa-306654.html

CVSS

7.8HIGH[email protected]

Attack Vector: LOCAL
Complexity: LOW
Privileges: LOW
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: HIGH
Integrity: HIGH
Availability: HIGH

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-829

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