High 7.5Known exploited (CISA KEV)Published Jun 8, 2021

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

Updated under an hour ago (2026-10-19 09:40 UTC)

Does this affect you?

It affects Microsoft Windows 10 Version 1809 and 16 other products. Add what you run to find out whether that includes you.

CISA lists it as known exploited since Nov 3, 2021; federal agencies had to remediate by Nov 17, 2021. Treat that date as your deadline.

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Every CVE for Microsoft Windows 10 Version 1809

Exploited in the last 30 days

Windows MSHTML Platform Remote Code Execution Vulnerability

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
Weakness (CWE): CWE-787
Known exploited: Added to CISA KEV Nov 3, 2021; federal remediation due Nov 17, 2021Apply updates per vendor instructions.
EPSS (exploitation in the next 30 days): 59.41% (percentile 99)
Assigned by: microsoft
NVD analysis: Analyzed
Record last updated: Oct 21, 2025
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Microsoft Windows 10 Version 1809 microsoft:windows_10_1809	from 10.0.0 before 10.0.17763.1999	CNA record
Microsoft Windows Server 2019 microsoft:windows_server_2019	from 10.0.0 before 10.0.17763.1999	CNA record
Microsoft Windows 10 Version 1909 microsoft:windows_10_1909	from 10.0.0 before 10.0.18363.1621	CNA record
Microsoft Windows 10 Version 21H1 microsoft:windows_10_21h1	from 10.0.0 before 10.0.19043.1052	CNA record
Microsoft Windows 10 Version 20H2 microsoft:windows_10_20h2	from 10.0.0 before 10.0.19042.1052	CNA record
Microsoft Windows 10 Version 1507 microsoft:windows_10_1507	from 10.0.0 before 10.0.10240.18967	CNA record
Microsoft Windows 10 Version 1607 microsoft:windows_10_1607	from 10.0.0 before 10.0.14393.4467	CNA record
Microsoft Windows Server 2016 microsoft:windows_server_2016	from 10.0.0 before 10.0.14393.4467	CNA record
Microsoft Windows 7 microsoft:windows_7	from 6.1.0 before 6.1.7601.25632; from 6.1.0 before publication	CNA record
Microsoft Windows 8.1 microsoft:windows_8.1	from 6.3.0 before 6.3.9600.20045; 6.3.0 builds before 1.0.0.0	CNA record
Microsoft Windows 8.1 microsoft:windows_rt_8.1	from 6.3.0 before 6.3.9600.20045; 6.3.0 builds before 1.0.0.0	CNA record
Microsoft Windows Server 2008 Service Pack 2 microsoft:windows_server_2008_sp2	from 6.0.0 before 6.0.6003.21137; from 6.0.0 before publication	CNA record
Microsoft Windows Server 2008 R2 Service Pack 1 microsoft:windows_server_2008_r2	from 6.1.0 before 6.1.7601.25632; from 6.1.0 before publication	CNA record
Microsoft Windows Server 2012 microsoft:windows_server_2012	from 6.2.0 before 6.2.9200.23372; 6.2.0 builds before 1.0.0.0	CNA record
Microsoft Windows Server 2012 R2 microsoft:windows_server_2012_r2	from 6.3.0 before 6.3.9600.20045; 6.3.0 builds before 1.0.0.0	CNA record
microsoft windows_10_1507 microsoft:windows_10_1507	before 10.0.10240.18967	NVD
microsoft windows_10_1607 microsoft:windows_10_1607	before 10.0.14393.4467	NVD
microsoft windows_10_1809 microsoft:windows_10_1809	before 10.0.17763.1999	NVD
microsoft windows_10_1909 microsoft:windows_10_1909	before 10.0.18363.1621	NVD
microsoft windows_10_2004 microsoft:windows_10_2004	before 10.0.19041.1052	NVD
microsoft windows_10_20h2 microsoft:windows_10_20h2	before 10.0.19042.1052	NVD
microsoft windows_10_21h1 microsoft:windows_10_21h1	before 10.0.19043.1052	NVD
microsoft windows_7 microsoft:windows_7	all versions	NVD
microsoft windows_8.1 microsoft:windows_8.1	all versions	NVD
microsoft windows_rt_8.1 microsoft:windows_rt_8.1	all versions	NVD
microsoft windows_server_2008 microsoft:windows_server_2008	r2; sp2	NVD
microsoft windows_server_2012 microsoft:windows_server_2012	all versions; r2	NVD
microsoft windows_server_2016 microsoft:windows_server_2016	before 10.0.14393.4467	NVD
microsoft windows_server_2019 microsoft:windows_server_2019	before 10.0.17763.1999	NVD

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33742x-refsource-misc, patch, vendor-advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33742us-government-resource

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.