CVE-2021-40444
8.8 · HIGH Actively ExploitedOverview
CVE-2021-40444 is a high-severity vulnerability affecting microsoft windows_10_1507. It was published on September 15, 2021 and has a CVSS 3.1 base score of 8.8 (HIGH). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.
This vulnerability has a CVSS 3.1 base score of 8.8, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
Microsoft is investigating reports of a remote code execution vulnerability in MSHTML that affects Microsoft Windows. Microsoft is aware of targeted attacks that attempt to exploit this vulnerability by using specially-crafted Microsoft Office documents.
An attacker could craft a malicious ActiveX control to be used by a Microsoft Office document that hosts the browser rendering engine. The attacker would then have to convince the user to open the malicious document. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
Microsoft Defender Antivirus and Microsoft Defender for Endpoint both provide detection and protections for the known vulnerability. Customers should keep antimalware products up to date. Customers who utilize automatic updates do not need to take additional action. Enterprise customers who manage updates should select the detection build 1.349.22.0 or newer and deploy i
Remediation
Check the references section for vendor advisories and patches from microsoft. Update windows_10_1507 to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| microsoft | windows_10_1507 | >= 0, < 10.0.10240.19060 | Affected |
| microsoft | windows_10_1607 | >= 0, < 10.0.14393.4651 | Affected |
| microsoft | windows_10_1809 | >= 0, < 10.0.17763.2183 | Affected |
| microsoft | windows_10_1909 | >= 0, < 10.0.18363.1801 | Affected |
| microsoft | windows_10_2004 | >= 0, < 10.0.19041.1237 | Affected |
| microsoft | windows_10_20h2 | >= 0, < 10.0.19042.1237 | Affected |
| microsoft | windows_10_21h1 | >= 0, < 10.0.19043.1237 | Affected |
| microsoft | windows_server_2004 | >= 0, < 10.0.19041.1237 | Affected |
| microsoft | windows_server_2016 | >= 0, < 10.0.14393.4651 | Affected |
| microsoft | windows_server_2019 | >= 0, < 10.0.17763.2183 | Affected |
| microsoft | windows_server_2022 | >= 0, < 10.0.20348.230 | Affected |
| microsoft | windows_server_20h2 | >= 0, < 10.0.19042.1237 | Affected |
References
Frequently Asked Questions
What is CVE-2021-40444?
CVE-2021-40444 is a high-severity vulnerability affecting microsoft windows_10_1507. It was published on September 15, 2021 and has a CVSS 3.1 base score of 8.8 (HIGH). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.
How severe is CVE-2021-40444?
This vulnerability has a CVSS 3.1 base score of 8.8, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2021-40444?
Check the references section for vendor advisories and patches from microsoft. Update windows_10_1507 to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-40444?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-40444 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
AI-driven PR review catches vulnerable dependencies before they ship.
Browser-based exploitation validates findings with real proof-of-concept.
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