CVE-2021-33742VulnerabilityPublished 11/03/2021Updated 10/24/2026

CVE-2021-33742: Microsoft Windows MSHTML Platform Remote Code Execution Vulnerability

Affects Microsoft WindowsSource CISA KEV

Severity

High

No CVSS score published yet

Exploitation: Actively exploited – in CISA KEV since 11/03/2021
KEV deadline: 11/17/2021
EPSS: 59.4% chance of exploitation in 30 days – higher than 99% of CVEs

What to do

CISA required action

Apply updates per vendor instructions.

nvd.nist.gov/vuln/detail/CVE-2021-33742 (opens in a new tab)

Description

CVE-2021-33742 is a high-severity remote code execution vulnerability in the Microsoft Windows MSHTML platform. It allows an attacker to execute arbitrary code remotely. This vulnerability has been exploited in the wild. No specific affected versions or patch information is provided in the available data.

Summary

Microsoft Windows MSHTML Platform contains an unspecified vulnerability (CVE-2021-33742) that enables remote code execution. The vulnerability is associated with weaknesses classified under CWE-787 (Out-of-bounds Write) and CWE-823 (Type Confusion). It has been confirmed to be exploited in the wild, indicating active threat usage. No detailed technical specifics or affected versions are provided in the source data.

Impact

Successful exploitation of this vulnerability allows remote attackers to execute arbitrary code on affected Windows systems, potentially leading to full system compromise. Given the exploitation in the wild, this poses a significant risk to affected users.

Mitigation

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no patch or official fix information is provided, users should monitor Microsoft security advisories closely and apply updates as soon as they become available.

CVE-2021-33742: Microsoft Windows MSHTML Platform Remote Code Execution Vulnerability

What to do

Description

Summary

Impact

Mitigation

Weaknesses

References

What to do

Description

AnalysisAI-generated, updated 10/24/2026, 09:19:50 UTC

Weaknesses

References

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