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 it across their environments. Microsoft Defender for Endpoint alerts will be displayed as: “Suspicious Cpl File Execution”. Upon completion of this investigation, Microsoft will take the appropriate action to help protect our customers. This may include providing a security update through our monthly release process or providing an out-of-cycle security update, depending on customer needs. Please see the Mitigations and Workaround sections for important information about steps you can take to protect your system from this vulnerability. UPDATE September 14, 2021: Microsoft has released security updates to address this vulnerability. Please see the Security Updates table for the applicable update for your system. We recommend that you install these updates immediately. Please see the FAQ for important information about which updates are applicable to your system.
Data as of 2 Nov 2026 · NVD, CISA KEV, EPSS
Defenders still triage vulnerabilities one CVE at a time, while increasingly automated attackers combine them at machine speed. Omenwave models the plausible pathways by which this CVE could be chained with others — surfacing them for research and awareness, with evidence for each step.
The source lands the attacker on the host (code execution or an established foothold), which satisfies the destination's requirement for local access.
A use-after-free vulnerability was discovered in Adobe Flash Player before 28.0.0.161. This vulnerability occurs due to a dangling pointer in the Pri…
The source lands the attacker on the host (code execution or an established foothold), which satisfies the destination's requirement for local access.
Flash Player versions 31.0.0.153 and earlier, and 31.0.0.108 and earlier have a use after free vulnerability. Successful exploitation could lead to a…
The source lands the attacker on the host (code execution or an established foothold), which satisfies the destination's requirement for local access.
Microsoft .NET Framework 2.0, 3.5, 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2 and 4.7 allow an attacker to execute code remotely via a malicious document or app…
The access level the source grants already meets or exceeds the access level the destination requires — the position carries over.
Active Directory Domain Services Elevation of Privilege Vulnerability
The source lands the attacker on the host (code execution or an established foothold), which satisfies the destination's requirement for local access.
An elevation of privilege vulnerability exists when an attacker establishes a vulnerable Netlogon secure channel connection to a domain controller, u…
Modelled plausible chaining potential derived from public CVE metadata (CVSS, CWE, CPE). Not a confirmed real-world exploit chain and contains no exploitation detail. For research and awareness only.
Methodology · Interactive explorer · JSON: /cve/CVE-2021-40444