.NET Framework
CVE-2019-0657 — .NET Framework and Visual Studio Spoofing Vulnerability
Executive Summary
A vulnerability exists in certain .Net Framework API's and Visual Studio in the way they parse URL's. An attacker who successfully exploited this vulnerability could use it to bypass security logic intended to ensure that a user-provided URL belonged to a specific hostname or a subdomain of that hostname. This could be used to cause privileged communication to be made to an untrusted service as if it was a trusted service. To exploit the vulnerability, an attacker must provide a URL string to an application that attempts to verify that the URL belongs to a specific hostname or to a subdomain of that hostname. The application must then make an HTTP request to the attacker-provided URL either directly or by sending a processed version of the attacker-provided URL to a web browser.
Overview
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
EPSS Score
0.04518
probability of exploitation in the next 30 days
0.90301 percentile - updated 2026-06-20
View on FIRST.org
Affected Products
87 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| .NET Core 1.0 | Release Notes (Security Update) |
Important | Spoofing | Maybe |
| .NET Core 2.1 | Release Notes (Security Update) |
Important | Spoofing | Maybe |
| .NET Core 2.2 | Release Notes (Security Update) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 2.0 Service Pack 2 on Windows Server 2008 for Itanium-Based Systems Service Pack 2 | 4487081 (Monthly Rollup) 4487124 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 3.0 Service Pack 2 on Windows Server 2008 for 32-bit Systems Service Pack 2 | 4487081 (Monthly Rollup) 4487124 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 3.0 Service Pack 2 on Windows Server 2008 for Itanium-Based Systems Service Pack 2 | 4487081 (Monthly Rollup) 4487124 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 3.0 Service Pack 2 on Windows Server 2008 for x64-based Systems Service Pack 2 | 4487081 (Monthly Rollup) 4487124 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 3.5 on Windows 10 for 32-bit Systems | 4487018 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 for x64-based Systems | 4487018 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1607 for 32-bit Systems | 4487026 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1607 for x64-based Systems | 4487026 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1703 for 32-bit Systems | 4487020 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1703 for x64-based Systems | 4487020 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1709 for 32-bit Systems | 4486996 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1709 for ARM64-based Systems | 4486996 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1709 for x64-based Systems | 4486996 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1803 for 32-bit Systems | 4487017 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1803 for ARM64-based Systems | 4487017 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1803 for x64-based Systems | 4487017 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1809 for 32-bit Systems | 4483452 (Monthly Rollup) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1809 for x64-based Systems | 4483452 (Monthly Rollup) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows 8.1 for 32-bit systems | 4483450 (Monthly Rollup) 4487123 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 3.5 on Windows 8.1 for x64-based systems | 4483450 (Monthly Rollup) 4487123 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 3.5 on Windows Server 2012 | 4487079 (Monthly Rollup) 4487122 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 3.5 on Windows Server 2012 (Server Core installation) | 4487079 (Monthly Rollup) 4487122 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 3.5 on Windows Server 2012 R2 | 4483450 (Monthly Rollup) 4487123 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 3.5 on Windows Server 2012 R2 (Server Core installation) | 4483450 (Monthly Rollup) 4487123 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 3.5 on Windows Server 2016 | 4487026 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows Server 2019 | 4483452 (Monthly Rollup) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows Server 2019 (Server Core installation) | 4483452 (Monthly Rollup) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows Server, version 1709 (Server Core Installation) | 4486996 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5 on Windows Server, version 1803 (Server Core Installation) | 4487017 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 3.5.1 on Windows 7 for 32-bit Systems Service Pack 1 | 4487078 (Monthly Rollup) 4487121 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 3.5.1 on Windows 7 for x64-based Systems Service Pack 1 | 4487078 (Monthly Rollup) 4487121 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 3.5.1 on Windows Server 2008 R2 for Itanium-Based Systems Service Pack 1 | 4487078 (Monthly Rollup) 4487121 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 3.5.1 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 | 4487078 (Monthly Rollup) 4487121 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 3.5.1 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) | 4487078 (Monthly Rollup) 4487121 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows 7 for 32-bit Systems Service Pack 1 | 4487078 (Monthly Rollup) 4487121 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows 7 for x64-based Systems Service Pack 1 | 4487078 (Monthly Rollup) 4487121 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows 8.1 for 32-bit systems | 4483450 (Monthly Rollup) 4487123 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows 8.1 for x64-based systems | 4483450 (Monthly Rollup) 4487123 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows RT 8.1 | 4483450 (Monthly Rollup) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2008 for 32-bit Systems Service Pack 2 | 4487081 (Monthly Rollup) 4487124 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2008 for x64-based Systems Service Pack 2 | 4487081 (Monthly Rollup) 4487124 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 | 4487078 (Monthly Rollup) 4487121 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) | 4487078 (Monthly Rollup) 4487121 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2012 | 4487079 (Monthly Rollup) 4487122 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2012 (Server Core installation) | 4487079 (Monthly Rollup) 4487122 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2012 R2 | 4483450 (Monthly Rollup) 4487123 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2012 R2 (Server Core installation) | 4483450 (Monthly Rollup) 4487123 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.6 on Windows Server 2008 for 32-bit Systems Service Pack 2 | 4487081 (Monthly Rollup) 4487124 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.6 on Windows Server 2008 for x64-based Systems Service Pack 2 | 4487081 (Monthly Rollup) 4487124 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows 10 Version 1607 for 32-bit Systems | 4487026 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows 10 Version 1607 for x64-based Systems | 4487026 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2016 | 4487026 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2016 (Server Core installation) | 4487026 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.6/4.6.1/4.6.2 on Windows 10 for 32-bit Systems | 4487018 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.6/4.6.1/4.6.2 on Windows 10 for x64-based Systems | 4487018 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 on Windows 7 for 32-bit Systems Service Pack 1 | 4487078 (Monthly Rollup) 4487121 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 on Windows 7 for x64-based Systems Service Pack 1 | 4487078 (Monthly Rollup) 4487121 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 on Windows 8.1 for 32-bit systems | 4483450 (Monthly Rollup) 4487123 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 on Windows 8.1 for x64-based systems | 4483450 (Monthly Rollup) 4487123 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 on Windows RT 8.1 | 4483450 (Monthly Rollup) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 | 4487078 (Monthly Rollup) 4487121 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) | 4487078 (Monthly Rollup) 4487121 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 | 4487079 (Monthly Rollup) 4487122 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 (Server Core installation) | 4487079 (Monthly Rollup) 4487122 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 R2 | 4483450 (Monthly Rollup) 4487123 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 R2 (Server Core installation) | 4483450 (Monthly Rollup) 4487123 (Security Only) |
Important | Spoofing | Maybe |
| Microsoft .NET Framework 4.7.1/4.7.2 on Windows 10 Version 1709 for 32-bit Systems | 4486996 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.7.1/4.7.2 on Windows 10 Version 1709 for ARM64-based Systems | 4486996 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.7.1/4.7.2 on Windows 10 Version 1709 for x64-based Systems | 4486996 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.7.1/4.7.2 on Windows Server, version 1709 (Server Core Installation) | 4486996 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.7.2 on Windows 10 Version 1803 for 32-bit Systems | 4487017 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.7.2 on Windows 10 Version 1803 for ARM64-based Systems | 4487017 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.7.2 on Windows 10 Version 1803 for x64-based Systems | 4487017 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.7.2 on Windows 10 Version 1809 for 32-bit Systems | 4483452 (Monthly Rollup) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.7.2 on Windows 10 Version 1809 for x64-based Systems | 4483452 (Monthly Rollup) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.7.2 on Windows Server 2019 | 4483452 (Monthly Rollup) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.7.2 on Windows Server 2019 (Server Core installation) | 4483452 (Monthly Rollup) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.7.2 on Windows Server, version 1803 (Server Core Installation) | 4487017 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.7/4.7.1/4.7.2 on Windows 10 Version 1703 for 32-bit Systems | 4487020 (Security Update) |
Important | Spoofing | Yes |
| Microsoft .NET Framework 4.7/4.7.1/4.7.2 on Windows 10 Version 1703 for x64-based Systems | 4487020 (Security Update) |
Important | Spoofing | Yes |
| Microsoft Visual Studio 2017 | Release Notes (Security Update) |
Important | Spoofing | Maybe |
| Microsoft Visual Studio 2017 version 15.9 (includes 15.0 - 15.8) | Release Notes (Security Update) |
Important | Spoofing | Maybe |
| PowerShell Core 6.1 | Release Notes (Security Update) |
Important | Spoofing | Yes |
| PowerShell Core 6.2 | Release Notes (Security Update) |
Important | Spoofing | Yes |
Patches
12 patches
| Article | Type | Restart |
|---|---|---|
Release Notes |
Security Update | Maybe |
4487081 (Monthly Rollup) 4487124 |
Monthly Rollup | Maybe |
4487018 |
Security Update | Yes |
4487026 |
Security Update | Yes |
4487020 |
Security Update | Yes |
4486996 |
Security Update | Yes |
4487017 |
Security Update | Yes |
4483452 |
Monthly Rollup | Yes |
4483450 (Monthly Rollup) 4487123 |
Monthly Rollup | Maybe |
4487079 (Monthly Rollup) 4487122 |
Monthly Rollup | Maybe |
4487078 (Monthly Rollup) 4487121 |
Monthly Rollup | Maybe |
4483450 |
Monthly Rollup | Maybe |
Known Exploits
No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.
Acknowledgments
Jonathan Birch of Microsoft Corporation
References
On This Page