CVE-2026-83763 in Windows
Summary
by MITRE • 10/14/2026
Access of resource using incompatible type ('type confusion') in Windows Input System allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described involves a critical flaw within the Microsoft Windows Input System, specifically categorized as a type confusion error that leads to unauthorized privilege escalation. This security issue arises from improper handling of data types during resource access operations, where the system fails to correctly validate or cast object types before processing them. In software engineering terms, this is a classic instance of CWE-843, Access of Resource Using Incompatible Type, which occurs when an application interprets memory as one type while it actually contains another, leading to undefined behavior and potential exploitation. The Windows Input System, responsible for managing user input from keyboards, mice, touch screens, and other peripherals, is a core component of the operating system with high-level privileges. A flaw in this subsystem allows an attacker who has already gained local access on the target machine to manipulate how these inputs are processed, thereby bypassing standard security controls.
An authorized attacker can leverage this vulnerability by crafting specific input sequences or manipulating internal data structures associated with the Input System. By triggering the type confusion condition, the attacker causes the system to execute code in a context that it should not have access to, typically resulting in arbitrary code execution within the kernel mode or a higher-privileged process space. This effectively allows the attacker to elevate their privileges from a standard user account to those of an administrator or even SYSTEM level, depending on the specific implementation details and the version of Windows affected. The operational impact is severe, as it grants complete control over the compromised system, enabling the installation of malware, theft of sensitive data, modification of security settings, and further lateral movement within a network environment.
From a threat intelligence perspective, this vulnerability aligns with MITRE ATT&CK techniques related to privilege escalation, such as T1068 Exploitation for Privilege Escalation or potentially T1055 Process Injection if the exploitation involves injecting code into another process. The attack vector is local (T1079), requiring physical access or prior compromise of a user account on the target system. Because it affects core operating system components, this flaw represents a significant risk to enterprise environments where multiple users share systems or where least-privilege principles are not strictly enforced across all endpoints.
Mitigation strategies primarily involve applying the latest security patches released by Microsoft for the affected Windows versions. Organizations should prioritize patching efforts on workstations and servers that run the vulnerable Input System components, particularly those exposed to untrusted input sources or used in multi-user environments. Additionally, implementing strict application whitelisting can help prevent unauthorized code execution even if an attacker successfully exploits this vulnerability. Regular security audits and monitoring for anomalous privilege escalation events are also recommended to detect potential exploitation attempts early. Maintaining up-to-date antivirus definitions and endpoint detection and response (EDR) solutions provides an additional layer of defense against post-exploitation activities that may follow the initial compromise.