CVE-2021-42554

SMM memory corruption vulnerability allowing a possible attacker to write fixed or predictable...

8.2 High

An issue was discovered in Insyde InsydeH2O with Kernel 5.0 before 05.08.42, Kernel 5.1 before 05.16.42, Kernel 5.2 before 05.26.42, Kernel 5.3 before 05.35.42, Kernel 5.4 before 05.42.51, and Kernel 5.5 before 05.50.51. An SMM memory corruption vulnerability in FvbServicesRuntimeDxe allows a possible attacker to write fixed or predictable data to SMRAM. Exploiting this issue could lead to escalating privileges to SMM.

Attack profile

How easy it is to exploit

Attack vector: Local
Complexity: Low
Privileges needed: High
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

0.33%Unchanged since Feb 3, 2022

What each source reports

NVD Score used 8.2

Record: CVE-2021-42554
CVSS 3.1: 8.2 HighCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
CVSS 2.0: 7.2 HighAV:L/AC:L/Au:N/C:C/I:C/A:C
Weakness: CWE-787
Updated: 2026-11-02

CVE List No score

Record: CVE-2021-42554
Updated: 2026-11-02

EUVDEUVD-2021-29522 No score

Record: EUVD-2021-29522
Updated: 2026-11-02

GitHub AdvisoriesGHSA-9hwg-wq94-95pr 8.2

SMM memory corruption vulnerability allowing a possible attacker to write fixed or predictable...

SMM memory corruption vulnerability allowing a possible attacker to write fixed or predictable data to SMRAM. Exploiting this issue could lead to escalating privileges to SMM.

Record: GHSA-9hwg-wq94-95pr
CVSS 3.1: 8.2 HighCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Weakness: CWE-787
Updated: 2026-11-02

Affected products

Show 22 moreShow less

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-42554 is a high vulnerability (CVSS 8.2) in Insyde Insydeh2o, published February 3, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.33%, the 25th percentile. No source names a fixed version.