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Vulnerabilities

Vulnerability · CVE-2021-33742

Microsoft Windows MSHTML Platform Remote Code Execution Vulnerability

Published Jun 3, 2021 · catalog updated Jun 16, 2026 · Microsoft Windows

Patch now

CVE-2021-33742 is in the CISA known-exploited catalog, due Nov 17, 2021. Confirm Microsoft Windows against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
High7.5
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
59.41%
Remediation
Remediation guidance
Affected products
cpe microsoft/windows 10 1507 · cpe microsoft/windows 10 1607 · cpe microsoft/windows 10 1809 · cpe microsoft/windows 10 1909 · cpe microsoft/windows 10 2004 · cpe microsoft/windows 10 20h2

Microsoft Windows MSHTML Platform contains an unspecified vulnerability that allows for remote code execution.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe microsoft/windows 10 1507version unspecified
  • cpe microsoft/windows 10 1607version unspecified
  • cpe microsoft/windows 10 1809version unspecified
  • cpe microsoft/windows 10 1909version unspecified
  • cpe microsoft/windows 10 2004version unspecified
  • cpe microsoft/windows 10 20h2version unspecified
  • cpe microsoft/windows 10 21h1version unspecified
  • cpe microsoft/windows 7version unspecified
  • vendor Microsoft Windowsversion unspecified

How to fix CVE-2021-33742

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-33742 is in the CISA known-exploited catalog, due Nov 17, 2021. Confirm Microsoft Windows against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply updates per vendor instructions.

What should an analyst verify?

CWE-787: Out-of-bounds Write; CWE-823. EPSS 59.41%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Windows security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 8, 2021 · Catalog

    Detected

    Microsoft Windows MSHTML Platform contains an unspecified vulnerability that allows for remote code execution.

  2. Nov 3, 2021 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Nov 17, 2021 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    Microsoft Windows MSHTML Platform contains an unspecified vulnerability that allows for remote code execution.

Sources

  • CISA KEVConfirmed exploitationCVE-2021-33742

    Microsoft Windows MSHTML Platform contains an unspecified vulnerability that allows for remote code execution.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2021-33742

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-33742

    30-day exploitation probability 59.4%

    first.org
  • NIST NVDVulnerability recordCVE-2021-33742

    Windows MSHTML Platform Remote Code Execution Vulnerability

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2021-33742

    Microsoft Windows MSHTML Platform contains an unspecified vulnerability that allows for remote code execution.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.