CVE-2021-26435

28

FAUCET Score

CVE-2021-26435 is a high-severity memory corruption vulnerability in the Windows Scripting Engine affecting numerous Microsoft Windows versions, including Windows 10, 7, 8.1, and various Server editions. This vulnerability, with a CVSS score of 8.1, allows for remote code execution if a user is tricked into opening a specially crafted file or visiting a malicious website. While not currently listed in CISA's KEV catalog or having public exploit code in Metasploit or ExploitDB, its high EPSS score and FAUCET Risk Score of 75/100 indicate a significant potential for future exploitation. It was addressed in the Microsoft September 2021 Patch Tuesday, which also fixed two zero-days.

Impacted Technologies

Vendor	Product	Version(s)	CPE
		Range not provided by sourceCPE matchmatch criteria	cpe:2.3:o:microsoft:windows_10:-:::::::*
		20h2CPE matchmatch criteria	cpe:2.3:o:microsoft:windows_10:20h2:::::::*
		21h1CPE matchmatch criteria	cpe:2.3:o:microsoft:windows_10:21h1:::::::*
		1607CPE matchmatch criteria	cpe:2.3:o:microsoft:windows_10:1607:::::::*
		1809CPE matchmatch criteria	cpe:2.3:o:microsoft:windows_10:1809:::::::*

CVSS Data

CVSS version used by this source: 3.1

8.1HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

NONE

Exploitability Score

2.8

Impact Score

5.2

CvssVersion

3.1

Exploit Intelligence

EPSS Score

4.81%

Probability of exploitation in next 30 days

EPSS Percentile

91.0%

Percentile rank of EPSS score among Peer Group

As of 2026-07-28

Model: v2026.06.15

This CVE's current EPSS score of 0.0481 is in the 91st percentile among its peer group of 14,875 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.2 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.1 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (43)

microsoftpatch availablevia nvd_reference

microsoftpatch availablevia msrc

Product: Windows 10 Version 1809 for 32-bit SystemsFixed in: 10.0.17763.2183

microsoftpatch availablevia msrc

Product: Windows 10 Version 1809 for x64-based SystemsFixed in: 10.0.17763.2183

microsoftpatch availablevia msrc

Product: Windows 10 Version 1809 for ARM64-based SystemsFixed in: 10.0.17763.2183

microsoftpatch availablevia msrc

Product: Windows Server 2019Fixed in: 10.0.17763.2183

microsoftpatch availablevia msrc

Product: Windows Server 2019 (Server Core installation)Fixed in: 10.0.17763.2183

microsoftpatch availablevia msrc

Product: Windows 10 Version 1909 for 32-bit SystemsFixed in: 10.0.18363.1801

microsoftpatch availablevia msrc

Product: Windows 10 Version 1909 for x64-based SystemsFixed in: 10.0.18363.1801

microsoftpatch availablevia msrc

Product: Windows 10 Version 1909 for ARM64-based SystemsFixed in: 10.0.18363.1801

microsoftpatch availablevia msrc

Product: Windows 10 Version 21H1 for x64-based SystemsFixed in: 10.0.19043.1237

microsoftpatch availablevia msrc

Product: Windows 10 Version 21H1 for ARM64-based SystemsFixed in: 10.0.19043.1237

microsoftpatch availablevia msrc

Product: Windows 10 Version 21H1 for 32-bit SystemsFixed in: 10.0.19043.1237

microsoftpatch availablevia msrc

Product: Windows Server 2022Fixed in: 10.0.20348.230

microsoftpatch availablevia msrc

Product: Windows Server 2022 (Server Core installation)Fixed in: 10.0.20348.230

microsoftpatch availablevia msrc

Product: Windows 10 Version 2004 for 32-bit SystemsFixed in: 10.0.19041.1237

microsoftpatch availablevia msrc

Product: Windows 10 Version 2004 for ARM64-based SystemsFixed in: 10.0.19041.1237

microsoftpatch availablevia msrc

Product: Windows 10 Version 2004 for x64-based SystemsFixed in: 10.0.19041.1237

microsoftpatch availablevia msrc

Product: Windows Server, version 2004 (Server Core installation)Fixed in: 10.0.19041.1237

microsoftpatch availablevia msrc

Product: Windows 10 Version 20H2 for x64-based SystemsFixed in: 10.0.19042.1237

microsoftpatch availablevia msrc

Product: Windows 10 Version 20H2 for 32-bit SystemsFixed in: 10.0.19042.1237

microsoftpatch availablevia msrc

Product: Windows 10 Version 20H2 for ARM64-based SystemsFixed in: 10.0.19042.1237

microsoftpatch availablevia msrc

Product: Windows Server, version 20H2 (Server Core Installation)Fixed in: 10.0.19042.1237

microsoftpatch availablevia msrc

Product: Windows 10 for 32-bit SystemsFixed in: 10.0.10240.19060

microsoftpatch availablevia msrc

Product: Windows 10 for x64-based SystemsFixed in: 10.0.10240.19060

microsoftpatch availablevia msrc

Product: Windows 10 Version 1607 for 32-bit SystemsFixed in: 10.0.14393.4651

microsoftpatch availablevia msrc

Product: Windows 10 Version 1607 for x64-based SystemsFixed in: 10.0.14393.4651

microsoftpatch availablevia msrc

Product: Windows Server 2016Fixed in: 10.0.14393.4651

microsoftpatch availablevia msrc

Product: Windows Server 2016 (Server Core installation)Fixed in: 10.0.14393.4651

microsoftpatch availablevia msrc

Product: Windows 7 for x64-based Systems Service Pack 1Fixed in: 6.1.7601.25712

microsoftpatch availablevia msrc

Product: Windows Server 2008 R2 for x64-based Systems Service Pack 1Fixed in: 6.1.7601.25712

microsoftpatch availablevia msrc

Product: Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)Fixed in: 6.1.7601.25712

microsoftpatch availablevia msrc

Product: Windows 7 for 32-bit Systems Service Pack 1Fixed in: 6.1.7601.25712

microsoftpatch availablevia msrc

Product: Windows 8.1 for 32-bit systemsFixed in: 6.3.9600.20120

microsoftpatch availablevia msrc

Product: Windows 8.1 for x64-based systemsFixed in: 6.3.9600.20120

microsoftpatch availablevia msrc

Product: Windows Server 2012 R2Fixed in: 6.3.9600.20120

microsoftpatch availablevia msrc

Product: Windows Server 2012 R2 (Server Core installation)Fixed in: 6.3.9600.20120

microsoftpatch availablevia msrc

Product: Windows RT 8.1Fixed in: 6.3.9600.20120

microsoftpatch availablevia msrc

Product: Windows Server 2008 for 32-bit Systems Service Pack 2Fixed in: 6.0.6003.21218

microsoftpatch availablevia msrc

Product: Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)Fixed in: 6.0.6003.21218

microsoftpatch availablevia msrc

Product: Windows Server 2008 for x64-based Systems Service Pack 2Fixed in: 6.0.6003.21218

microsoftpatch availablevia msrc

Product: Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)Fixed in: 6.0.6003.21218

microsoftpatch availablevia msrc

Product: Windows Server 2012Fixed in: 6.2.9200.23462

microsoftpatch availablevia msrc

Product: Windows Server 2012 (Server Core installation)Fixed in: 6.2.9200.23462

Vendor Advisories (1)

microsoft2021-Sep/CVE-2021-26435Critical

Windows Scripting Engine Memory Corruption Vulnerability

References

portal.msrc.microsoft.com / en-US/security-guidance/advisory/CVE-2021-26435

PatchVendor Advisory