.NET Framework
CVE-2019-0820 — .NET Framework and .NET Core Denial of Service Vulnerability
Executive Summary
A denial of service vulnerability exists when .NET Framework and .NET Core improperly process RegEx strings. An attacker who successfully exploited this vulnerability could cause a denial of service against a .NET application. A remote unauthenticated attacker could exploit this vulnerability by issuing specially crafted requests to a .NET Framework (or .NET core) application. The update addresses the vulnerability by correcting how .NET Framework and .NET Core applications handle RegEx string processing.
Overview
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
EPSS Score
0.05876
probability of exploitation in the next 30 days
0.9226 percentile - updated 2026-06-20
View on FIRST.org
Affected Products
108 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| .NET Core 1.0 | Release Notes (Security Update) |
Important | Denial of Service | Maybe |
| .NET Core 1.1 | Release Notes (Security Update) |
Important | Denial of Service | Maybe |
| .NET Core 2.1 | Release Notes (Security Update) |
Important | Denial of Service | Maybe |
| .NET Core 2.2 | Release Notes (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 2.0 Service Pack 2 on Windows Server 2008 for 32-bit Systems Service Pack 2 | 4499409 (Monthly Rollup) 4498964 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 2.0 Service Pack 2 on Windows Server 2008 for Itanium-Based Systems Service Pack 2 | 4499409 (Monthly Rollup) 4498964 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 2.0 Service Pack 2 on Windows Server 2008 for x64-based Systems Service Pack 2 | 4499409 (Monthly Rollup) 4498964 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.0 Service Pack 2 on Windows Server 2008 for 32-bit Systems Service Pack 2 | 4499409 (Monthly Rollup) 4498964 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.0 Service Pack 2 on Windows Server 2008 for Itanium-Based Systems Service Pack 2 | 4499409 (Monthly Rollup) 4498964 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.0 Service Pack 2 on Windows Server 2008 for x64-based Systems Service Pack 2 | 4499409 (Monthly Rollup) 4498964 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5 on Windows 10 for 32-bit Systems | 4499154 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 for x64-based Systems | 4499154 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1607 for 32-bit Systems | 4494440 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1607 for x64-based Systems | 4494440 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1703 for 32-bit Systems | 4499181 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1703 for x64-based Systems | 4499181 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1709 for 32-bit Systems | 4499179 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1709 for ARM64-based Systems | 4499179 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1709 for x64-based Systems | 4499179 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1803 for 32-bit Systems | 4499167 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1803 for ARM64-based Systems | 4499167 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1803 for x64-based Systems | 4499167 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1809 for 32-bit Systems | 4499405 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1809 for x64-based Systems | 4499405 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1903 for 32-bit Systems | 4495620 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5 on Windows 10 Version 1903 for x64-based Systems | 4495620 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5 on Windows 8.1 for 32-bit systems | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5 on Windows 8.1 for x64-based systems | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5 on Windows Server 2012 | 4499407 (Monthly Rollup) 4498962 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5 on Windows Server 2012 (Server Core installation) | 4499407 (Monthly Rollup) 4498962 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5 on Windows Server 2012 R2 | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5 on Windows Server 2012 R2 (Server Core installation) | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5 on Windows Server 2016 | 4494440 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 3.5 on Windows Server 2016 (Server Core installation) | 4494440 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 3.5 on Windows Server 2019 | 4499405 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5 on Windows Server 2019 (Server Core installation) | 4499405 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5 on Windows Server, version 1803 (Server Core Installation) | 4499167 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 3.5 on Windows Server, version 1903 (Server Core installation) | 4495620 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5.1 on Windows 7 for 32-bit Systems Service Pack 1 | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5.1 on Windows 7 for x64-based Systems Service Pack 1 | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5.1 on Windows Server 2008 R2 for Itanium-Based Systems Service Pack 1 | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5.1 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 3.5.1 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows 7 for 32-bit Systems Service Pack 1 | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows 7 for x64-based Systems Service Pack 1 | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows 8.1 for 32-bit systems | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows 8.1 for x64-based systems | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows RT 8.1 | 4499408 (Monthly Rollup) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2008 for 32-bit Systems Service Pack 2 | 4499409 (Monthly Rollup) 4498964 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2008 for x64-based Systems Service Pack 2 | 4499409 (Monthly Rollup) 4498964 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2012 | 4499407 (Monthly Rollup) 4498962 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2012 (Server Core installation) | 4499407 (Monthly Rollup) 4498962 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2012 R2 | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.5.2 on Windows Server 2012 R2 (Server Core installation) | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.6 on Windows Server 2008 for 32-bit Systems Service Pack 2 | 4499409 (Monthly Rollup) 4498964 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.6 on Windows Server 2008 for x64-based Systems Service Pack 2 | 4499409 (Monthly Rollup) 4498964 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2016 | 4494440 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2016 (Server Core installation) | 4494440 (Security Update) |
Important | Denial of Service | 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 | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | 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 | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | 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 | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | 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 | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | 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 | 4499408 (Monthly Rollup) |
Important | Denial of Service | 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 | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | 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) | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 | 4499407 (Monthly Rollup) 4498962 (Security Only) |
Important | Denial of Service | 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) | 4499407 (Monthly Rollup) 4498962 (Security Only) |
Important | Denial of Service | 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 | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | 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) | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.7.2 on Windows 10 Version 1803 for 32-bit Systems | 4499167 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 4.7.2 on Windows 10 Version 1803 for ARM64-based Systems | 4499167 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 4.7.2 on Windows 10 Version 1803 for x64-based Systems | 4499167 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 4.7.2 on Windows Server 2019 | 4499405 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.7.2 on Windows Server 2019 (Server Core installation) | 4499405 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.7.2 on Windows Server, version 1803 (Server Core Installation) | 4499167 (Security Update) |
Important | Denial of Service | Yes |
| Microsoft .NET Framework 4.8 on Windows 10 Version 1607 for 32-bit Systems | 4495610 (Security Update) |
Important | Denial of Service | Unknown |
| Microsoft .NET Framework 4.8 on Windows 10 Version 1607 for x64-based Systems | 4495610 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows 10 Version 1703 for 32-bit Systems | 4495611 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows 10 Version 1703 for x64-based Systems | 4495611 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows 10 Version 1709 for 32-bit Systems | 4495613 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows 10 Version 1709 for x64-based Systems | 4495613 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows 10 Version 1803 for 32-bit Systems | 4495616 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows 10 Version 1803 for x64-based Systems | 4495616 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows 10 Version 1809 for 32-bit Systems | 4499405 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows 10 Version 1809 for x64-based Systems | 4499405 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows 10 Version 1903 for 32-bit Systems | 4495620 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows 10 Version 1903 for x64-based Systems | 4495620 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows 7 for 32-bit Systems Service Pack 1 | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows 7 for x64-based Systems Service Pack 1 | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows 8.1 for 32-bit systems | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows 8.1 for x64-based systems | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows RT 8.1 | 4499408 (Monthly Rollup) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) | 4499406 (Monthly Rollup) 4498961 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows Server 2012 | 4499407 (Monthly Rollup) 4498962 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows Server 2012 (Server Core installation) | 4499407 (Monthly Rollup) 4498962 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows Server 2012 R2 | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows Server 2012 R2 (Server Core installation) | 4499408 (Monthly Rollup) 4498963 (Security Only) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows Server 2016 | 4495610 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows Server 2016 (Server Core installation) | 4495610 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows Server 2019 | 4499405 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows Server 2019 (Server Core installation) | 4499405 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows Server, version 1803 (Server Core Installation) | 4495616 (Security Update) |
Important | Denial of Service | Maybe |
| Microsoft .NET Framework 4.8 on Windows Server, version 1903 (Server Core installation) | 4495620 (Security Update) |
Important | Denial of Service | Maybe |
| PowerShell Core 6.1 | Release Notes (Security Update) |
Important | Denial of Service | Maybe |
| PowerShell Core 6.2 | Release Notes (Security Update) |
Important | Denial of Service | Maybe |
Patches
17 patches
| Article | Type | Restart |
|---|---|---|
Release Notes |
Security Update | Maybe |
4499409 (Monthly Rollup) 4498964 |
Monthly Rollup | Maybe |
4499154 |
Security Update | Yes |
4494440 |
Security Update | Yes |
4499181 |
Security Update | Yes |
4499179 |
Security Update | Yes |
4499167 |
Security Update | Yes |
4499405 |
Security Update | Maybe |
4495620 |
Security Update | Maybe |
4499408 (Monthly Rollup) 4498963 |
Monthly Rollup | Maybe |
4499407 (Monthly Rollup) 4498962 |
Monthly Rollup | Maybe |
4499406 (Monthly Rollup) 4498961 |
Monthly Rollup | Maybe |
4499408 |
Monthly Rollup | Maybe |
4495610 |
Security Update | Unknown |
4495611 |
Security Update | Maybe |
4495613 |
Security Update | Maybe |
4495616 |
Security Update | 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
Microsoft has not published researcher acknowledgments for this CVE, or they are not yet reflected in our data source. Check the MSRC advisory directly for the most current credit information.
References
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