CVE-2026-83520

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Deserialization of Untrusted Data in .NET Framework

Publication date: 2026-10-13

Last updated on: 2026-10-14

Assigner: Microsoft Corporation

Description

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

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-10-13

Last Modified

2026-10-14

Generated

2026-10-19

AI Q&A

2026-10-14

EPSS Evaluated

2026-10-18

NVD

CVE-2026-83520

EUVD

EUVD-2026-100198

Affected Vendors & Products

Vendor	Product	Version / Range
Microsoft	.NET	10.0 10.0.0
Microsoft	.NET	11.0 11.0.0
Microsoft	.NET	8.0 8.0.0
Microsoft	.NET	9.0 9.0.0
Microsoft	Microsoft	.NET Framework 3.5 3.5.0
Microsoft	Microsoft	.NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 3.0.0.0
Microsoft	Microsoft	.NET Framework 3.5 AND 4.7.2 4.7.0
Microsoft	Microsoft	.NET Framework 3.5 AND 4.8 4.8.0
Microsoft	Microsoft	.NET Framework 3.5 AND 4.8.1 4.8.1
Microsoft	Microsoft	.NET Framework 4.6.2/4.7/4.7.1/4.7.2 4.7.0
Microsoft	Microsoft	.NET Framework 4.8 4.8.0
Microsoft	Microsoft	.NET Framework 4.8.1 4.8.0.0
Microsoft	Microsoft	Visual Studio 2022 version 17.14 17.14.0
Microsoft	Microsoft	Visual Studio 2026 version 18.10 18.10.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-502	The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

Attack-Flow Graph

Executive Summary

This vulnerability involves deserialization of untrusted data in .NET applications. An attacker can exploit this to execute arbitrary code remotely over a network without authentication.

Detection Guidance

Detecting this vulnerability requires monitoring for unusual deserialization activity in .NET applications. Check application logs for unexpected deserialization events or network traffic patterns indicative of exploitation. Use tools like Wireshark to inspect network traffic for malformed payloads targeting .NET deserialization endpoints.

Impact Analysis

An attacker could gain control of your system, steal data, install malware, or disrupt services. It may lead to unauthorized access to sensitive information or complete system compromise.

Compliance Impact

This vulnerability could lead to data breaches, violating GDPR and HIPAA requirements for data protection and confidentiality. Organizations may face fines or legal consequences for failing to address it.

Mitigation Strategies

Apply the latest security updates from Microsoft for .NET Framework and Visual Studio as soon as possible. Monitor Microsoft's update guide for patches and disable deserialization of untrusted data if not required.

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