CVE-2025-21276

FAQ

According to the CVSS metric, successful exploitation of this vulnerability has a high impact on availability (A:H). What does that mean for this vulnerability?

An attacker can send specially crafted packets which could affect availability of the service and result in Denial of Service (DoS).

The Security Updates table indicates that this vulnerability affects all supported versions of Microsoft Windows. Why are IE Cumulative updates listed for Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, and Windows Server 2012 R2?

While Microsoft has announced retirement of the Internet Explorer 11 application on certain platforms and the Microsoft Edge Legacy application is deprecated, the underlying MSHTML, EdgeHTML, and scripting platforms are still supported. The MSHTML platform is used by Internet Explorer mode in Microsoft Edge as well as other applications through WebBrowser control. The EdgeHTML platform is used by WebView and some UWP applications. The scripting platforms are used by MSHTML and EdgeHTML but can also be used by other legacy applications. Updates to address vulnerabilities in the MSHTML platform and scripting engine are included in the IE Cumulative Updates; EdgeHTML and Chakra changes are not applicable to those platforms.

To stay fully protected, we recommend that customers who install Security Only updates install the IE Cumulative updates for this vulnerability.