CVE-2026-83520: .NET Remote Code Execution Vulnerability

Overview

Severity
High (CVSS 8.8)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Category
Remote Code Execution
Exploit Status
Not Exploited
Exploitation Likelihood
Less Likely
Patch Tuesday
2026-Oct
Released
2026-10-13

Description

Deserialization of untrusted data in .NET allows an unauthorized attacker to execute code over a network.

FAQ

According to the CVSS metric, the attack vector is network (AV:N) and user interaction is required (UI:R). What is the target context of the remote code execution? This attack requires a user to open a specially crafted file from the attacker to initiate remote code execution.

Affected Products (33)

Developer Tools

  • Microsoft Visual Studio 2026 version 18.10
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 version 21H2
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 version 22H2
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 24H2
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 25H2
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2025
  • Microsoft .NET Framework 4.8.1 on Windows 11 version 26H1
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 23H2
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2022
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 version 26H2
  • .NET 11.0 installed on Windows
  • .NET 10.0 installed on Windows
  • .NET 8.0 installed on Windows
  • .NET 9.0 installed on Windows
  • Microsoft Visual Studio 2022 version 17.14
  • Microsoft .NET Framework 3.5 on Windows 11 version 26H1
  • Microsoft .NET Framework 3.5 on Windows Server 2012
  • Microsoft .NET Framework 3.5 on Windows Server 2012 R2
  • Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows 10 version 1607
  • Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2016
  • Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2019
  • Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 version 1809
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 version 1809
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 version 21H2
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 version 22H2
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2019
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2022
  • Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012
  • Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 R2
  • Microsoft .NET Framework 4.8 on Windows 10 version 1607
  • Microsoft .NET Framework 4.8 on Windows Server 2012
  • Microsoft .NET Framework 4.8 on Windows Server 2012 R2
  • Microsoft .NET Framework 4.8 on Windows Server 2016

Security Updates (23)

Acknowledgments

<a href="https://x.com/soaj1664ashar">Dr.-Ing Ashar Javed</a>, <a href="https://vincent55.tw/">Vincent55 Yang</a>

Revision History

  • 2026-10-13: Information published.