What’s Vulnerable › Vulnerabilities

CVE-2021-26701: .NET Core Remote Code Execution Vulnerability

• Severity: high (CVSS 7.5 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 30.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-02-25 · updated 2026-06-17

Description

.NET Core Remote Code Execution Vulnerability

Affected products

• Fedoraproject Fedora: 32, 33, 34
• Microsoft .NET: from 5.0 before 5.0.4 — fixed in 5.0.4
• Microsoft Corporation .NET Core: from 2.1 before 2.1.28; from 3.1 before 3.1.15 — fixed in 2.1.28, 3.1.15
• Microsoft PowerShell Core: 7.0, 7.1
• Microsoft Visual Studio 2019: from 16.0 through 16.9
• 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 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 (includes 16.0 - 16.7): from 16.0 before publication — fixed in publication
• Microsoft Visual Studio 2019 version 16.9 (includes 16.0 - 16.8): from 15.0.0 before publication — fixed in publication
• Microsoft PowerShell Core 7.0: from 7.0.0 before publication — fixed in publication
• Microsoft PowerShell Core 7.1: from 7.1.0 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
• Microsoft Visual Studio 2019 for Mac: from 8.0.0 before publication — fixed in publication

How to fix

Upgrade to a fixed version: Microsoft .NET 5.0.4; Microsoft Corporation .NET Core 2.1.28, 3.1.15; Microsoft .NET 5.0 publication; Microsoft .NET Core 2.1 publication; Microsoft .NET Core 3.1 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 (includes 16.0 - 16.7) publication; Microsoft Visual Studio 2019 version 16.9 (includes 16.0 - 16.8) publication; Microsoft PowerShell Core 7.0 publication; Microsoft PowerShell Core 7.1 publication; Microsoft Visual Studio 2017 version 15.9 (includes 15.0 - 15.8) publication. Check the vendor advisory for mitigations.

References

• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/S2AZOUKMCHT2WBHR7MYDTYXWOBHZW5P5/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TW3ZSJTTMZAFKGW7NJWTVVFZUYYU2SJZ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UBOSSX7U6BSHV5RI74FCOW4ITJ5RRJR5/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WA5WQJVHUL5C4XMJTLY3C67R4WP35EF4/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XPUKFHIGP5YNJRRFWKDJ2XRS4WTFJNNK/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YLFATXASXW4OV2ZBSRP4G55HJH73QPBP/
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26701
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/S2AZOUKMCHT2WBHR7MYDTYXWOBHZW5P5/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TW3ZSJTTMZAFKGW7NJWTVVFZUYYU2SJZ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UBOSSX7U6BSHV5RI74FCOW4ITJ5RRJR5/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WA5WQJVHUL5C4XMJTLY3C67R4WP35EF4/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XPUKFHIGP5YNJRRFWKDJ2XRS4WTFJNNK/

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