Microsoft Net Framework 4.0 V 30319 Vulnerabilities Jun 2026

Attackers can send specially crafted requests that cause the .NET application to consume excessive resources, crashing the application or the server.

Get-ChildItem 'HKLM:\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full' | Get-ItemPropertyValue -Name Release -EA 0

This article explores the critical vulnerabilities associated with version 4.0.30319, how attackers exploit them, and the necessary steps to secure your environment. The Significance of Version 4.0.30319

Microsoft ASP.NET Forms authentication bypass - Vulnerabilities microsoft net framework 4.0 v 30319 vulnerabilities

The Forms Authentication feature in .NET 4.0 has been identified as having a bypass vulnerability, allowing remote authenticated users to access arbitrary accounts using crafted usernames. Information Disclosure:

: The framework fails to properly sanitize specific crafted input values passing through the ASP.NET subsystem, allowing remote attackers to run malicious scripts or inject arbitrary HTML directly into client browsers.

Many security tools report vulnerabilities based solely on this CLR version string, even if you have a modern, fully patched version like .NET 4.8 installed. Attackers can send specially crafted requests that cause the

— .NET Framework RCE

Framework-level vulnerabilities (e.g., CVE-2015-2504) allow attackers to inject malicious scripts into web applications. More recent app-specific vulnerabilities like CVE-2024-51026 still target systems using this runtime version.

If you see 4.0.30319 in a production environment today, it is to all patched .NET Framework issues from 2016 onward. Information Disclosure: : The framework fails to properly

The primary issue with .NET Framework 4.0 is its age. It does not contain the security patches, hardening, and modern cryptographic standards included in later versions (e.g., .NET 4.5, 4.6, 4.7, 4.8).

These formatters are inherently unsafe when processing untrusted input. An attacker can craft a malicious serialized payload. When the .NET 4.0 application deserializes this payload, it triggers unintended code execution path workflows, allowing the attacker to run arbitrary commands on the host server. 2. XML External Entity (XXE) Processing

Original RTM did not enforce proper ciphertext integrity for view state. Only fixed with the ASP.NET security update (MS10-070) released in September 2010—meaning unpatched RTM is vulnerable.