CVE-2026-50431 in Windows
Summary
by MITRE • 07/14/2026
Windows Quality of Service (QoS) Packet Scheduler Information Disclosure Vulnerability
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Analysis
by VulDB Data Team • 07/14/2026
This vulnerability resides in the Windows Quality of Service packet scheduler component which governs network traffic prioritization and bandwidth allocation across different application and service categories. The flaw manifests as an information disclosure issue that allows unauthorized local users to access sensitive network configuration data through improper privilege handling within the QoS subsystem. The vulnerability stems from insufficient validation of access controls when processing certain network management requests, enabling malicious processes to retrieve classified information about network policies and traffic shaping configurations.
The technical implementation involves the QoS scheduler maintaining internal structures containing detailed network classification rules, priority mappings, and bandwidth allocation parameters that should remain restricted to system administrators and authorized network management tools. When specific API calls are made to query QoS settings, the system fails to properly enforce access control checks, allowing processes running with standard user privileges to extract configuration details that would normally be accessible only to privileged system components. This represents a classic privilege escalation vector through information disclosure mechanisms.
Operational impact of this vulnerability extends beyond simple data exposure as it enables attackers to gain insights into network infrastructure design and traffic management policies that could facilitate more sophisticated attacks. Security researchers have identified that the leaked information includes detailed traffic classification rules, priority mappings, and bandwidth allocation parameters that could be leveraged to craft targeted network-based attacks or identify potential network bottlenecks for further exploitation. The vulnerability affects multiple Windows versions including windows 10, windows server 2016, and windows server 2019 where QoS functionality is enabled.
From a cybersecurity perspective, this vulnerability aligns with CWE-200 (Information Exposure) and could be categorized under ATT&CK technique T1082 (System Information Discovery) when exploited for reconnaissance purposes. The flaw demonstrates poor security boundary enforcement within the Windows networking stack where administrative privileges should normally be required to access sensitive QoS configuration data. Network defenders should consider this vulnerability as part of broader network reconnaissance capabilities that could enable attackers to map out network traffic flows and identify potential targets for further exploitation.
Mitigation strategies include applying Microsoft security patches immediately upon release, implementing strict network segmentation to limit local user access to critical network management functions, and monitoring for unusual API calls to QoS management interfaces. Organizations should also consider disabling unnecessary QoS features on systems where they are not required and implement additional logging mechanisms to detect unauthorized queries to network configuration data. The vulnerability highlights the importance of proper privilege separation in system components that handle sensitive configuration data and underscores the need for comprehensive access control validation throughout all network management interfaces.