CVE-2026-61937 in Windows
Summary
by MITRE • 08/11/2026
Integer overflow or wraparound in Windows HTTP.sys allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability represents a critical integer overflow condition within the Windows HTTP.sys kernel driver that enables local privilege escalation for authenticated attackers. The flaw occurs when the http.sys component processes certain HTTP requests, specifically in how it handles integer arithmetic during buffer allocation operations. When legitimate HTTP requests are crafted with maliciously constructed parameters, the system performs integer arithmetic that results in an overflow or wraparound condition, causing the application to allocate insufficient memory buffers. This memory allocation error creates a potential for arbitrary code execution within the kernel context, which can be exploited by local users who already possess valid credentials to gain elevated privileges.
The technical implementation of this vulnerability stems from improper input validation and integer handling within the HTTP.sys driver's request processing pipeline. According to CWE-190, this corresponds to an integer overflow condition where a computation produces a result that exceeds the maximum value representable by the data type. The attack vector requires local system access with valid user credentials, making it a local privilege escalation vulnerability rather than a remote one. This places the vulnerability in the context of ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation' and specifically addresses scenarios where attackers leverage existing access to escalate their privileges within the system.
The operational impact of this vulnerability extends beyond simple privilege escalation as it creates a persistent backdoor mechanism that can be leveraged by attackers who maintain local presence on compromised systems. The vulnerability affects all supported versions of Windows including Windows 7, Windows 8, Windows Server 2008, and subsequent releases through Windows 10. Once successfully exploited, the attacker gains kernel-level privileges which enables complete system compromise, data exfiltration, and persistence mechanisms that can evade traditional endpoint protection solutions.
Mitigation strategies for this vulnerability include immediate deployment of Microsoft security patches through Windows Update or manual installation of the relevant security bulletin patches. System administrators should also implement least privilege access controls to minimize the impact of potential exploitation, ensuring that local user accounts have minimal required permissions. Network segmentation and monitoring of HTTP traffic can help detect anomalous request patterns that might indicate exploitation attempts. Additionally, implementing behavioral monitoring solutions that can detect kernel-level memory manipulation activities can provide early warning detection capabilities. The vulnerability highlights the importance of proper input validation and integer overflow protection in kernel-mode drivers, emphasizing the need for comprehensive security testing during software development lifecycle processes to prevent similar issues from manifesting in production environments.