CVE-2026-70162 in Visual Studio
Summary
by MITRE • 10/14/2026
A denial of service vulnerability exists when Microsoft Common Object Runtime Library improperly handles web requests. An attacker who successfully exploited this vulnerability could cause a denial of service against a .NET web application. A remote unauthenticated attacker could exploit this vulnerability by issuing specially crafted requests to the .NET application. The update addresses the vulnerability by correcting how the .NET web application handles web requests.
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Analysis
by VulDB Data Team • 10/14/2026
The Microsoft Common Object Runtime Library, commonly known as the CLR or part of the .NET Framework, contains a critical flaw related to its handling of incoming HTTP traffic. This specific weakness allows for a denial of service condition when the runtime processes malformed or specially crafted web requests. The vulnerability stems from an improper validation and processing mechanism within the request pipeline, where the system fails to correctly manage resource allocation or state transitions in response to anomalous input patterns. When such inputs are received, the CLR may enter an unstable state, leading to thread exhaustion, memory leaks, or unhandled exceptions that crash the hosting process. This behavior effectively renders the associated .NET web application unavailable to legitimate users, disrupting business operations and service continuity.
From a technical perspective, this vulnerability is classified under CWE-400, which denotes Uncontrolled Resource Consumption. The root cause lies in the lack of robust input sanitization or rate limiting within the specific component responsible for parsing HTTP headers or body content. An attacker can exploit this by sending high-volume requests with specific structural anomalies that trigger internal loops or excessive memory allocation without corresponding cleanup procedures. Because the flaw resides in the core runtime library, it affects a wide range of applications built on .NET technologies, making it particularly dangerous as it does not require application-specific code to be vulnerable; rather, any service relying on this version of the CLR is susceptible if exposed to network traffic.
The operational impact of exploiting this vulnerability is severe for organizations hosting public-facing web services. A successful attack results in a complete denial of service, meaning that authorized users cannot access critical applications or data hosted by the affected system. Since the exploit requires no authentication, it can be launched remotely by unauthenticated attackers using automated tools to flood the target with crafted requests. This ease of exploitation makes it attractive for distributed denial of service campaigns aimed at disrupting online services, causing financial loss and reputational damage. The vulnerability aligns with ATT&CK technique T1499, Endpoint Denial of Service, as it involves overwhelming system resources to degrade performance or cause a crash through network-based attacks.
To mitigate this risk, organizations must apply the latest security updates provided by Microsoft that correct how the .NET web application handles these specific types of requests. These patches typically include enhanced validation logic and resource management protocols within the CLR to prevent the conditions that lead to crashes. In addition to applying vendor-supplied fixes, administrators should implement network-level defenses such as Web Application Firewalls configured to detect and block anomalous request patterns or excessive traffic volumes from single sources. Rate limiting and connection throttling can also help mitigate the impact of such attacks by ensuring no single client can overwhelm the server resources. Regular monitoring for unusual spikes in error logs related to HTTP processing will aid in early detection, while maintaining up-to-date patch management policies ensures that known vulnerabilities are addressed promptly before they can be exploited in the wild.