Summary
Impact: Security Feature Bypass. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.
Details
According to the CVSS metric, successful exploitation could lead to a scope change (S:C). What does this mean for this vulnerability?
In this case, a successful attack could be performed from a low privilege AppContainer. The attacker could elevate their privileges and execute code or access resources at a higher integrity level than that of the AppContainer execution environment.
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.
Are the updates for Windows 10 for x64-based Systems and Windows 10 for 32-bit Systems currently available?
Yes. As of April 9, 2025, the security update (5055547) for Windows 10 for x64-based Systems and Windows 10 for 32-bit Systems are available. Customers running Windows 10 should ensure the update is installed to be protected from this vulnerability.
What kind of security feature could be bypassed by successfully exploiting this vulnerability?
A URL path could be constructed by an attacker in such a way that the URL’s Zone is interpreted as belonging to a more privileged zone
According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do?
The user would have to click on a specially crafted URL to be compromised by the attacker.
Security updates
10.0.17763.7136 — https://support.microsoft.com/help/5055519
10.0.20348.3453 — https://support.microsoft.com/help/5055526
10.0.19044.5737 — https://support.microsoft.com/help/5055518
10.0.22621.5189 — https://support.microsoft.com/help/5055528
10.0.26100.3775 — https://support.microsoft.com/help/5055523
10.0.25398.1551 — https://support.microsoft.com/help/5055527
10.0.10240.20978 — https://support.microsoft.com/help/5055547
10.0.14393.7969 — https://support.microsoft.com/help/5055521
6.0.6003.23220 — https://support.microsoft.com/help/5055609
6.0.6003.23220 — https://support.microsoft.com/help/5055596
1.000 — https://support.microsoft.com/en-us/help/5055515
6.1.7601.27670 — https://support.microsoft.com/help/5055561
6.1.7601.27670 — https://support.microsoft.com/help/5055570
6.2.9200.25423 — https://support.microsoft.com/help/5055581
6.3.9600.22523 — https://support.microsoft.com/help/5055557
Vulnerabilities 1
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High 8.6
Windows Security Zone Mapping Security Feature Bypass Vulnerability
Improper input validation in Windows Security Zone Mapping allows an unauthorized attacker to bypass a security feature locally.
Revision history
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#2
The security updates for Windows 10 for 32-bit Systems and Windows 10 for x64-based Systems are now available. See the Security Updates table for more information.
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#1
Information published.
References
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CVE-2025-27737 Windows Security Zone Mapping Security Feature Bypass Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-27737
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Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
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Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
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Common Vulnerability Scoring System
https://www.first.org/cvss