CVE-2021-33742
Published: November 3, 2021
Official Description
Microsoft Windows MSHTML Platform contains an unspecified vulnerability that allows for remote code execution.
CISA KEV Advisory
Microsoft Windows MSHTML Platform Remote Code Execution Vulnerability
Microsoft Windows MSHTML Platform contains an unspecified vulnerability that allows for remote code execution.
Apply updates per vendor instructions.
Risk Analysis
This unspecified vulnerability in the Microsoft Windows MSHTML Platform enables remote code execution. Its high EPSS score of 0.71001 and inclusion in CISA's KEV indicate a high likelihood of exploitation and confirmed active attacks, making it a critical threat.
This vulnerability is actively exploited in the wild. The remote code execution capability implies it can be triggered without direct physical access to the affected system.
It is imperative to apply all available security updates for Microsoft Windows to patch the MSHTML Platform. System hardening and user awareness regarding suspicious files or links are also recommended.
Technical Analysis
CVE-2021-33742 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2021-33742 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Affected Vendors & Products
Exploit & PoC Resources
All References (1)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-33742 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1