CVE-2025-21269

FAQ

According to the CVSS metrics, successful exploitation of this vulnerability could lead to some loss of confidentiality (C:L) but have no effect on integrity (I:N) or on availability (A:N). What does that mean for this vulnerability?

An attacker who successfully exploited the vulnerability could view some sensitive information (Confidentiality) but not all resources within the impacted component may be divulged to the attacker. The attacker cannot make changes to disclosed information (Integrity) or limit access to the resource (Availability).

According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do?

Exploitation of the vulnerability requires that a user open a specially crafted file.

• In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file.
• In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) containing a specially crafted file designed to exploit the vulnerability.

An attacker would have no way to force users to visit the website. Instead, an attacker would have to convince users to click a link, typically by way of an enticement in an email or instant message, and then convince them to open the specially crafted file.

What kind of security feature could be bypassed by successfully exploiting this vulnerability?

A security feature bypass vulnerability exists when the MSHTML platform fails to validate the correct Security Zone of requests for specific URLs. This could allow an attacker to cause a user to access a URL in a less restricted Internet Security Zone than intended.

To exploit this vulnerability, an attacker could email or otherwise provide a specially crafted URL to a victim and convince them to click on it.

The security update addresses the vulnerability by correcting security feature behavior to properly map affected URLs to the correct Security Zone.

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.