CVE-2026-50659

Analyzed Analyzed - Analysis Complete

.NET Output Encoding Flaw Enables Spoofing

Publication date: 2026-07-14

Last updated on: 2026-07-24

Assigner: Microsoft Corporation

Description

Improper encoding or escaping of output in .NET allows an authorized attacker to perform spoofing over a network.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-07-14

Last Modified

2026-07-24

Generated

2026-08-04

AI Q&A

2026-07-15

EPSS Evaluated

2026-08-02

NVD

CVE-2026-50659

EUVD

EUVD-2026-44407

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	.net_framework	4.8.1
microsoft	.net_framework	4.8
microsoft	.net_framework	4.6.2
microsoft	.net_framework	4.7
microsoft	.net_framework	4.7.1
microsoft	.net_framework	4.7.2
microsoft	.net	From 8.0.0 (inc) to 8.0.29 (exc)
microsoft	.net	From 9.0.0 (inc) to 9.0.18 (exc)
microsoft	.net	From 10.0.0 (inc) to 10.0.6 (exc)
microsoft	.net_framework	3.5
microsoft	visual_studio_2022	From 17.12.0 (inc) to 17.12.22 (exc)
microsoft	visual_studio_2022	From 17.14.0 (inc) to 17.14.36 (exc)
microsoft	visual_studio_2026	From 18.7.0 (inc) to 18.7.4 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-116	The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.

Attack-Flow Graph

Executive Summary

This vulnerability involves improper encoding or escaping of output in .NET. An authorized attacker can exploit this to perform spoofing over a network, potentially deceiving users or systems into believing malicious content is legitimate.

Detection Guidance

This vulnerability involves improper encoding or escaping in .NET applications. Detection requires reviewing .NET application logs for suspicious input/output patterns or unexpected behavior in web responses. Check for encoded or malformed data in HTTP headers, URLs, or form inputs that may indicate spoofing attempts.

Impact Analysis

An attacker could trick users into interacting with malicious content by spoofing trusted sources. This may lead to unauthorized actions, data exposure, or further compromise of systems relying on .NET applications.

Compliance Impact

Spoofing risks could lead to unauthorized data access or breaches, violating GDPR (data protection) or HIPAA (health data privacy). Non-compliance may result in legal penalties or reputational damage.

Mitigation Strategies

Apply the latest security updates from Microsoft for .NET to address improper encoding or escaping issues. Monitor Microsoft's update guide for patches and verify their installation on affected systems.

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