HIGHCVSS 8.8Actively exploited · CISA KEV since 2021-11-03Vulnerability

CVE-2021-40444

Microsoft MSHTML contains a unspecified vulnerability that allows for remote code execution.

Properties

Euvd product
Windows Server 2008 R2 Service Pack 1 (Server Core installation), Windows 8.1, Windows Server 2019 (Server Core installation), Windows 10 Version 20H2, Windows Server 2012, Windows 10 Version 2004, Windows Server 2019, Windows Server version 20H2, Windows Server 2012 R2 (Server Core installation), Windows Server 2012 (Server Core installation), Windows Server version 2004, Windows Server 2008 Service Pack 2 (Server Core installation), Windows 10 Version 21H1, Windows 10 Version 1809, Windows Server 2008 R2 Service Pack 1, Windows Server 2016, Windows 10 Version 1607, Windows Server 2016 (Server Core installation), Windows Server 2022, Windows 10 Version 1507, Windows 7 Service Pack 1, Windows 7, Windows 10 Version 1909, Windows Server 2008 Service Pack 2, Windows Server 2012 R2
Vulnerability name
Microsoft MSHTML Remote Code Execution Vulnerability
First seen
2026-08-10T15:10:57+00:00
Cvss score
8.8
Epss score
0.9784
Last seen
2026-10-19T12:00:27+00:00
Due date
2021-11-17
Euvd assigner
microsoft
Retrieved at
2026-10-21T01:24:47+00:00
Exploited euvd since
2021-11-03T00:00:00+00:00
Src batch id
epss_history-20261020T103617Z-728ddd
Source url
https://epss.empiricalsecurity.com/epss_scores-2026-10-19.csv.gz
Date added
2021-11-03
Euvd base score version
3.1
Score
8.8
Fetched at
2026-10-20T10:36:20+00:00
Euvd vendor
Microsoft
Cvss vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L
In Signal since
initial import (Sep 2026)
Euvd base score
8.8

Related Entities (22)

AFFECTS_PRODUCT (19)

→[Product]cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_server_2004:*:*:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_10_20h2:*:*:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_7:-:sp1:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_10_1507:*:*:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_10_1909:*:*:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_10_2004:*:*:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_server_20h2:*:*:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_server_2012:-:r2:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*
→[Product]cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_rt_8.1:-:*:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
→[Product]cpe:2.3:o:microsoft:windows_10_21h1:*:*:*:*:*:*:*:*

DESCRIBES (1)

←[KEVEntry]Microsoft MSHTML Remote Code Execution Vulnerability

HAS_WEAKNESS (1)

→[Weakness]Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

INVOLVES (1)

←[Signal]kev_added · 2021-11-03

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CVE-2021-40444 (CVSS 8.8) — Ninja Signal Threat Intelligence | Ninja Signal