CVE-2026-61366 in Windows
Summary
by MITRE • 08/11/2026
Double free in Windows Network Connection Broker allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 08/11/2026
The vulnerability described represents a critical double free condition within the Windows Network Connection Broker service that enables authenticated attackers to achieve local privilege escalation. This flaw exists in the memory management handling of network connection broker components, where improper deallocation of memory resources creates opportunities for exploitation. The Network Connection Broker service operates with elevated privileges to manage network connectivity states and maintain system network awareness, making it an attractive target for privilege escalation attacks. When a malicious user with legitimate login credentials interacts with this service, the double free condition can be triggered through crafted inputs or specific API calls that manipulate memory allocation patterns.
The technical implementation of this vulnerability stems from inadequate memory management practices within the broker service's handling of network connection objects and associated resources. A double free occurs when the same memory block is freed twice, potentially allowing an attacker to manipulate heap metadata or control data structures in ways that can be leveraged for code execution or privilege elevation. The flaw typically manifests during normal operation when multiple pathways exist to deallocate the same memory resource, creating a scenario where the heap allocator's internal bookkeeping becomes corrupted. This corruption enables attackers to inject malicious data into allocated memory regions or redirect execution flow through controlled memory layout manipulation.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with persistent access to elevated system capabilities. Local privilege escalation means that an attacker who has already established a foothold on a system can leverage this flaw to gain SYSTEM level privileges, which would normally require more sophisticated exploitation techniques or physical access. Once elevated, the attacker can manipulate system files, disable security features, install backdoors, and access sensitive data across all user sessions. The Network Connection Broker's role in maintaining persistent network connectivity also means that an attacker with elevated privileges could maintain long-term access while potentially remaining undetected by standard monitoring systems.
Mitigation strategies for this vulnerability require immediate patch application from Microsoft as the primary defense mechanism, since the flaw exists within core Windows system components that cannot be easily modified without official updates. System administrators should prioritize deployment of relevant security patches and monitor for any exploitation attempts through unusual network connection patterns or unexpected privilege escalation events. Additional defensive measures include implementing least privilege principles to limit user access to network connection broker functionality, enabling application control policies to restrict unauthorized execution, and deploying monitoring solutions that can detect anomalous heap manipulation behaviors. The vulnerability aligns with CWE-415 which addresses double free conditions in memory management, and represents a technique that could be categorized under ATT&CK tactic TA0004 (Privilege Escalation) and technique T1068 (Local Privilege Escalation). Organizations should also consider implementing runtime protection mechanisms such as heap spraying prevention and control flow integrity checks to mitigate potential exploitation attempts.