Advisory Published


First published: Fri Oct 01 2021(Updated: )

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.

Credit: cve@mitre.org

Affected SoftwareAffected VersionHow to fix
Insyde InsydeH2O>=5.3<5.34.44
Insyde InsydeH2O>=5.2<5.25.44
Insyde InsydeH2O>=5.1<5.16.25
Insyde InsydeH2O>=5.4<5.42.44
Insyde InsydeH2O>=5.3<5.35.25
Insyde InsydeH2O>=5.2<5.26.25
Insyde InsydeH2O>=5.4<5.43.25
Siemens Ruggedcom Apr1808 Firmware
Siemens Ruggedcom Apr1808
Siemens Simatic Field Pg M5 Firmware
Siemens Simatic Field Pg M5
Siemens Simatic Field Pg M6 Firmware
Siemens Simatic Field Pg M6
Siemens Simatic Ipc127e Firmware
Siemens Simatic Ipc127e
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Siemens Simatic Ipc227g
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Siemens Simatic Ipc277g
Siemens Simatic Ipc327g Firmware
Siemens Simatic Ipc327g
Siemens Simatic Ipc377g Firmware
Siemens Simatic Ipc377g
Siemens Simatic Ipc427e Firmware
Siemens Simatic Ipc427e
Siemens Simatic Ipc477e Firmware
Siemens Simatic Ipc477e
Siemens Simatic Ipc477e Pro Firmware
Siemens Simatic Ipc477e Pro
Siemens Simatic Ipc627e Firmware
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Siemens Simatic Ipc647e Firmware
Siemens Simatic Ipc647e
Siemens Simatic Ipc677e Firmware
Siemens Simatic Ipc677e
Siemens Simatic Ipc847e Firmware
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Siemens Simatic Itp1000 Firmware
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Frequently Asked Questions

  • What is CVE-2021-33626?

    CVE-2021-33626 is a vulnerability that exists in the SMM (System Management Mode) branch, allowing an attacker to corrupt data in SMRAM memory and execute arbitrary code.

  • Which software is affected by CVE-2021-33626?

    Insyde InsydeH2O versions 5.3 to 5.34.44, 5.2 to 5.25.44, 5.1 to 5.16.25, 5.4 to 5.42.44, 5.3 to 5.35.25, 5.2 to 5.26.25, 5.4 to 5.43.25, Siemens Ruggedcom Apr1808 Firmware

  • What is the severity of CVE-2021-33626?

    The severity of CVE-2021-33626 is high (7.8).

  • How can I fix CVE-2021-33626?

    Apply the recommended security patches provided by the software vendors or follow the mitigation steps outlined in the advisories.

  • Where can I find more information about CVE-2021-33626?

    You can find more information about CVE-2021-33626 in the provided references: [1] [2] [3]


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