CVE-2026-96233 in .NET
Summary
by MITRE • 10/14/2026
Out-of-bounds write in ASP.NET Core allows an unauthorized attacker to deny service over a network.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described constitutes a critical out-of-bounds write flaw within the ASP.NET Core framework, specifically impacting services exposed over network interfaces. This type of memory corruption error occurs when the application writes data beyond the allocated boundaries of a buffer in system memory. In the context of web frameworks like ASP.NET Core, such flaws often arise during the parsing or processing of incoming HTTP requests where input validation is insufficient or logic errors lead to incorrect pointer arithmetic. An attacker who can send specially crafted network packets containing malformed headers, payloads, or query parameters can trigger this condition. The immediate consequence of an out-of-bounds write is unpredictable behavior within the application process, ranging from data corruption and crashes to arbitrary code execution if the memory layout allows for control flow hijacking. However, in many scenarios involving web servers, the most consistent and reliable outcome is a denial of service, as the operating system typically terminates the affected process upon detecting invalid memory access via segmentation faults or similar protection mechanisms.
From a technical perspective, this vulnerability aligns with Common Weakness Enumeration identifier CWE-787, which classifies out-of-bounds writes as a category of memory safety errors. These weaknesses are particularly dangerous because they bypass standard type-safety checks and can lead to privilege escalation if the web server process runs with elevated system privileges. The attack vector is classified under MITRE ATT&CK technique T1498, Network Denial of Service, specifically focusing on resource exhaustion through application layer attacks. By exploiting this flaw, an attacker does not necessarily need authentication credentials, making it a remote unauthenticated vulnerability that poses a significant risk to public-facing web applications built on ASP.NET Core. The impact extends beyond simple downtime; if the server crashes repeatedly, it can lead to cascading failures in dependent services or load balancers configured with health checks that do adequately handle such transient errors.
Mitigation strategies for this vulnerability require immediate attention from system administrators and development teams. The primary defense is applying the latest security patches provided by Microsoft for ASP.NET Core, as vendors typically release updates that address memory safety issues through code fixes in the underlying runtime or framework libraries. Until patching can be implemented, network-level mitigations should be employed to reduce exposure. This includes configuring web application firewalls to inspect and block suspicious HTTP requests that exhibit patterns consistent with buffer overflow attempts, such as unusually long headers or malformed content types. Additionally, restricting access to sensitive endpoints through IP whitelisting or authentication requirements can limit the attack surface available to unauthorized actors. It is also advisable to run ASP.NET Core applications in isolated environments using containers or sandboxing technologies to contain potential crashes and prevent them from affecting other processes on the host system. Regular security audits and static code analysis tools that detect memory safety violations should be integrated into the development lifecycle to identify similar vulnerabilities before deployment.