CVE-2021-33627

Medium

Elevated severity or exploit probability.

CVSS base

8.2 HIGH

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

EPSS — probability of exploitation (30 days)

0.3%

26.1th percentile

CISA KEV

Not listed

Weakness / dates

CWE-119

Published 2022-02-03 · modified 2026-08-11

CVSS breakdown

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Attack Vector	L	Local
Attack Complexity	L	Low
Privileges Required	H	High
User Interaction	N	None
Scope	C	Changed
Confidentiality	H	High
Integrity	H	High
Availability	H	High

Timeline

2022-02-03 — Published (NVD)
2026-08-11 — Last modified (NVD)

Description

An issue was discovered in Insyde InsydeH2O Kernel 5.0 before 05.09.11, 5.1 before 05.17.11, 5.2 before 05.27.11, 5.3 before 05.36.11, 5.4 before 05.44.11, and 5.5 before 05.52.11 affecting FwBlockServiceSmm. Software SMI services that use the Communicate() function of the EFI_SMM_COMMUNICATION_PROTOCOL do not check whether the address of the buffer is valid, which allows use of SMRAM, MMIO, or OS kernel addresses.

Affected

insyde siemens

References

Official: NVD · CVE.org