What’s Vulnerable › Vulnerabilities

CVE-2020-1108: .NET Core & .NET Framework Denial of Service Vulnerability

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 6.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-05-21 · updated 2026-08-19

Description

A denial of service vulnerability exists when .NET Core or .NET Framework improperly handles web requests. An attacker who successfully exploited this vulnerability could cause a denial of service against a .NET Core or .NET Framework web application. The vulnerability can be exploited remotely, without authentication. A remote unauthenticated attacker could exploit this vulnerability by issuing specially crafted requests to the .NET Core or .NET Framework application. The update addresses the vulnerability by correcting how the .NET Core or .NET Framework web application handles web requests.

Affected products

• Microsoft .NET: 5.0-preview1, 5.0-preview2, 5.0-preview3
• Microsoft Corporation .NET Core: from 2.1 through 2.1.18; from 3.0 through 3.1.4; 2.1, 3.1
• Microsoft .NET Framework: 2.0-sp2, 3.0-sp2, 4.6, 3.5, 4.5.2, 4.6.1 (+6)
• Microsoft Powershell: 7.0
• Microsoft PowerShell Core: 6.2
• Microsoft Visual Studio 2017 version 15.9 (includes 15.0 - 15.8): 15.9
• Microsoft Visual Studio 2019: 16.0, 16.4, 16.5
• Microsoft .NET 5.0: from 5.0.0 before publication — fixed in publication
• Microsoft .NET Core 2.1: from 2.1 before publication — fixed in publication
• Microsoft .NET Core 3.1: from 3.1 before publication — fixed in publication
• Microsoft .NET Framework 2.0 Service Pack 2: from 2.0.0 before publication — fixed in publication
• Microsoft .NET Framework 3.0 Service Pack 2: from 3.0.0 before publication — fixed in publication
• Microsoft .NET Framework 3.5: from 3.5.0 before publication — fixed in publication
• Microsoft .NET Framework 3.5.1: from 3.5.0 before publication — fixed in publication
• Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2: from 3.0.0.0 before publication — fixed in publication
• Microsoft .NET Framework 3.5 AND 4.6/4.6.1/4.6.2: from 3.5.0 before publication — fixed in publication
• Microsoft .NET Framework 3.5 AND 4.7.1/4.7.2: from 3.0 before publication — fixed in publication
• Microsoft .NET Framework 3.5 AND 4.7.2: from 4.7.0 before publication — fixed in publication
• Microsoft .NET Framework 3.5 AND 4.8: from 4.8.0 before publication — fixed in publication
• Microsoft .NET Framework 4.5.2: from 4.0.0.0 before publication — fixed in publication
• Microsoft .NET Framework 4.6: from 4.0.0.0 before publication — fixed in publication
• Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2: from 4.0.0.0 before publication — fixed in publication
• Microsoft .NET Framework 4.8: from 4.8.0 before publication — fixed in publication
• Microsoft Visual Studio 2019 version 16.0: from 16.0 before publication — fixed in publication
• Microsoft Visual Studio 2019 version 16.4 (includes 16.0 - 16.3): from 16.0 before publication — fixed in publication
• Microsoft Visual Studio 2019 version 16.5: from 16.0 before publication — fixed in publication
• Microsoft PowerShell 7.0: from 7.0.0 before publication — fixed in publication
• Microsoft PowerShell Core 6.2: from 6.0 before publication — fixed in publication
• Microsoft Visual Studio 2017 version 15.9 (includes 15.0 - 15.8): from 15.9.0 before publication — fixed in publication

How to fix

Upgrade to a fixed version: Microsoft .NET 5.0 publication; Microsoft .NET Core 2.1 publication; Microsoft .NET Core 3.1 publication; Microsoft .NET Framework 2.0 Service Pack 2 publication; Microsoft .NET Framework 3.0 Service Pack 2 publication; Microsoft .NET Framework 3.5 publication; Microsoft .NET Framework 3.5.1 publication; Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 publication; Microsoft .NET Framework 3.5 AND 4.6/4.6.1/4.6.2 publication; Microsoft .NET Framework 3.5 AND 4.7.1/4.7.2 publication; Microsoft .NET Framework 3.5 AND 4.7.2 publication; Microsoft .NET Framework 3.5 AND 4.8 publication. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-1108
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1108

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