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Vulnerability record · CVE-2021-33626 · published 1 October 2021

CVE-2021-33626: Insydeh2o inclusion from untrusted sphere vulnerability

Insyde · Insydeh2o

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.

7.8 CVSS 3.1 High EPSS 0.31% · top 78.8% CWE-829 · Inclusion from untrusted sphere
7.8CVSS 3.1 base score, v2 4.6
0.31%EPSS exploitation probability, 30 days
NoNot in CISA KEV
17Affected product versions listed by NVD
10References
11 Aug 2026Last modified by NVD

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.

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

Affected products

17 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://cert-portal.siemens.com/productcert/pdf/ssa-306654.pdf Third Party Advisory
https://security.netapp.com/advisory/ntap-20220216-0006/ Third Party Advisory
https://www.insyde.com/security-pledge Vendor Advisory
https://www.insyde.com/security-pledge/SA-2021001 Vendor Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-306654.pdf Third Party Advisory
https://security.netapp.com/advisory/ntap-20220216-0006/ Third Party Advisory
https://www.insyde.com/security-pledge Vendor Advisory
https://www.insyde.com/security-pledge/SA-2021001 Vendor Advisory
https://www.kb.cert.org/vuls/id/796611
https://cert-portal.siemens.com/productcert/html/ssa-306654.html

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2017-5689Intel AMT, ISM and SBT improper privilege management allows privilege escalationIntel manageability SKUs (AMT, ISM, SBT) contain an improper privilege management flaw. An unprivileged network attacker can gain system privileges o…KEVEPSS 92%analysed9.8CVE-2023-39281Insydeh2o out-of-bounds write vulnerabilityA stack buffer overflow vulnerability discovered in AsfSecureBootDxe in Insyde InsydeH2O with kernel 5.0 through 5.5 allows attackers to run arbitrar…EPSS 0.49%9.8CVE-2021-41842Insydeh2o vulnerabilityAn issue was discovered in AtaLegacySmm in the kernel 5.0 before 05.08.46, 5.1 before 05.16.46, 5.2 before 05.26.46, 5.3 before 05.35.46, 5.4 before …EPSS 1.5%8.8CVE-2023-22613Insydeh2o out-of-bounds write vulnerabilityAn issue was discovered in IhisiSmm in Insyde InsydeH2O with kernel 5.0 through 5.5. It is possible to write to an attacker-controlled address. An at…EPSS 0.21%8.8CVE-2023-22612Insydeh2o out-of-bounds write vulnerabilityAn issue was discovered in IhisiSmm in Insyde InsydeH2O with kernel 5.0 through 5.5. A malicious host OS can invoke an Insyde SMI handler with malfor…EPSS 0.23%8.8CVE-2023-22614Insydeh2o out-of-bounds write vulnerabilityAn issue was discovered in ChipsetSvcSmm in Insyde InsydeH2O with kernel 5.0 through 5.5. There is insufficient input validation in BIOS Guard update…EPSS 0.38%8.4CVE-2023-22615Insydeh2o out-of-bounds write vulnerabilityAn issue was discovered in IhisiSmm in Insyde InsydeH2O with kernel 5.0 through 5.5. IHISI subfunction execution may corrupt SMRAM. An attacker can p…EPSS 0.20%8.2CVE-2022-36448Insydeh2o improper input validation vulnerabilityAn issue was discovered in Insyde InsydeH2O with kernel 5.0 through 5.5. There is an SMM memory corruption vulnerability in the Software SMI handler …EPSS 0.34%

Source: NIST National Vulnerability Database (record CVE-2021-33626), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.