30319 Vulnerabilities | Microsoft Net Framework 4.0 V

| Attack Vector | Prerequisite | Exploit Availability | |---------------|--------------|----------------------| | Public-facing ASP.NET web app | .NET 4.0, Forms Auth enabled | Metasploit module for CVE-2010-3332 | | WCF / .NET Remoting endpoint on internet | Unpatched TCP/HTTP channel | Public PoC for deserialization (CVE-2017-0248) | | Local privilege escalation | Malicious app running on same server | Use BinaryFormatter on untrusted data | | Email / file upload parsers | App uses XAML or XPS handling | CVE-2015-6092 (XAML Browser Applications) |

Real-world exploitation: CVE-2017-8759 (SOAP WSDL parser) — though originally .NET 3.5, similar deserialization flaws existed in .NET 4.0.30319 until patched in Oct 2017.

The most critical class of vulnerabilities affecting .NET 4.0 involves Remote Code Execution. These flaws allow attackers to run arbitrary code on a victim's machine without user interaction, often through malicious files or network requests.

Microsoft .NET Framework 4.0, with its specific build version 4.0.30319, was a landmark release in Microsoft’s software development platform. Released alongside Visual Studio 2010 and Windows Server 2008 R2, it introduced significant improvements in parallel computing, managed extensibility, and the Core Common Language Runtime (CLR). microsoft net framework 4.0 v 30319 vulnerabilities

However, version 4.0.30319 is now considered legacy and out-of-support (mainstream support ended in 2016, extended support ended in 2021). As a result, unpatched installations of this exact version contain numerous critical vulnerabilities that expose systems to remote code execution, privilege escalation, and denial-of-service attacks.

Important Note: The version string 4.0.30319 refers to the CLR build number. This same base version appears across Windows 7, Windows Server 2008 R2, and later OSes—but the vulnerability status depends entirely on the patch level (update rollup) applied to that build.

A hospital runs a patient scheduling tool built in 2011 on .NET 4.0.30319 (RTM). The tool uses WCF over net.tcp. An attacker gains low-privilege access via a phishing email. Using a known WCF deserialization exploit (similar to CVE-2017-8759), they escalate to SYSTEM privileges, then move laterally across the domain. | Attack Vector | Prerequisite | Exploit Availability

Severity: Critical (CVSS 8.2)
Affected Components: .NET Framework’s SOAP WSDL parser.

This vulnerability allowed an unauthenticated attacker to execute arbitrary code on a target system. By sending a maliciously crafted document (e.g., a .RTF or .DOCX file) containing a custom WSDL (Web Services Description Language) payload, an attacker could bypass security controls.

A dangerous misconception is that installing a newer .NET runtime (e.g., 4.8) "upgrades" an application compiled for 4.0. It does not. Microsoft

| CVE ID | Vulnerability | CVSS Score | |--------|---------------|-------------| | CVE-2015-2504 | .NET Framework Information Disclosure via WCF | 5.0 (Medium) | | CVE-2013-0005 | WCF Insecure Transport Security Bypass | 6.8 (Medium) |

Description: Windows Communication Foundation (WCF) in .NET 4.0.30319 improperly validates certain message security bindings. Attackers on the same network segment could downgrade encryption or inject plaintext data into encrypted WCF streams.

Microsoft .NET Framework 4.0 (version 4.0.30319) in its unpatched state is dangerously vulnerable to multiple remote code execution, privilege escalation, and information disclosure attacks. The framework’s core components—remoting, serialization, ASP.NET view state, and regex engine—contain design weaknesses that were only partially fixed in later updates.

Organizations still running this exact base version must:

Leaving this version exposed on a production network is a security incident waiting to happen.