What’s Vulnerable › Vulnerabilities

CVE-2021-1723: ASP.NET Core and Visual Studio Denial of Service Vulnerability

• Severity: medium (CVSS 5.0 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 5.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-01-12 · updated 2026-06-17

Description

ASP.NET Core and Visual Studio Denial of Service Vulnerability

Affected products

• Fedoraproject Fedora: 32, 33
• Microsoft .NET Core: from 3.1 through 3.1.10; from 5.0 through 5.0.1
• Microsoft Visual Studio 2019: from 16.0 through 16.8
• Microsoft ASP.NET Core 3.1: from 3.0 before publication — fixed in publication
• Microsoft ASP.NET Core 5.0: from 5.0 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 16.7 (includes 16.0 – 16.6): from 16.0.0 before publication — fixed in publication
• Microsoft Visual Studio 2019 version 16.8: from 16.0 before publication — fixed in publication

How to fix

Upgrade to a fixed version: Microsoft ASP.NET Core 3.1 publication; Microsoft ASP.NET Core 5.0 publication; Microsoft Visual Studio 2019 version 16.4 (includes 16.0 - 16.3) publication; Microsoft Visual Studio 2019 version 16.7 (includes 16.0 – 16.6) publication; Microsoft Visual Studio 2019 version 16.8 publication. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-1723
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-1723

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