CVE-2025-49761 in Windows
Summary
by MITRE • 08/12/2025
Use after free in Windows Kernel allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 11/21/2025
The vulnerability identified as CVE-2025-49761 represents a critical use-after-free condition within the Windows kernel that enables authenticated local attackers to achieve privilege escalation. This flaw exists in the kernel-mode components responsible for memory management and resource handling, creating a scenario where freed memory regions can be accessed and manipulated by malicious code. The vulnerability stems from improper handling of object references and memory deallocation sequences that fail to properly invalidate pointers or prevent subsequent access to deallocated resources. According to CWE-416, this classification specifically addresses use-after-free conditions where memory is accessed after it has been freed, making it a direct implementation of the well-known memory safety vulnerability pattern. The attack vector requires local system access and authentication, meaning an adversary must first establish a legitimate user session before exploiting this weakness to gain elevated privileges.
The technical implementation of this vulnerability occurs within kernel-level memory management subsystems where objects are allocated and subsequently freed during normal system operations. When the kernel fails to properly track object references or maintain proper synchronization during deallocation processes, it creates opportunities for attackers to manipulate the freed memory space. The use-after-free condition typically manifests when an attacker can control the contents of freed memory before it is reallocated to another object, allowing for arbitrary code execution or privilege escalation. This particular flaw affects Windows operating systems where kernel memory management routines do not adequately enforce memory access controls or object lifecycle management. The vulnerability is particularly concerning because it operates at the kernel level, where any successful exploitation immediately grants the attacker the highest possible system privileges, effectively bypassing all user-mode security controls and access restrictions.
The operational impact of CVE-2025-49761 extends beyond simple privilege escalation, as it represents a fundamental breakdown in the kernel's memory management security model. Attackers who successfully exploit this vulnerability can bypass standard security boundaries and gain complete system control without requiring additional attack vectors or complex multi-stage exploits. The local nature of the attack means that adversaries need only authenticate to the system, which can be achieved through various legitimate means such as user accounts, service accounts, or even compromised credentials from previous attacks. This makes the vulnerability particularly dangerous in enterprise environments where multiple user accounts and service accounts exist, as any authenticated user could potentially exploit this weakness. The privilege escalation achieved through this use-after-free condition allows attackers to execute arbitrary code with kernel-level privileges, enabling them to modify system files, install rootkits, disable security services, and establish persistent access to the compromised system. According to ATT&CK framework, this vulnerability maps directly to privilege escalation techniques under the T1068 category, specifically targeting the kernel and system-level privileges.
Mitigation strategies for CVE-2025-49761 focus on both immediate patching and operational security measures to reduce the attack surface. Microsoft has released security updates addressing this vulnerability, which should be deployed immediately across all affected systems. Organizations should implement strict access controls and privilege management policies to minimize the number of authenticated users with local access to critical systems. The principle of least privilege should be enforced, ensuring that only necessary accounts have local authentication capabilities. Additionally, system monitoring and anomaly detection should be enhanced to identify potential exploitation attempts, particularly unusual memory access patterns or privilege escalation activities. Network segmentation and endpoint protection solutions can help detect and prevent lateral movement once an attacker has established a foothold. Regular security assessments and vulnerability scanning should include checks for proper memory management implementation and ensure that kernel components are functioning correctly. The vulnerability also highlights the importance of secure coding practices and memory management in kernel development, emphasizing the need for comprehensive code reviews and static analysis tools to identify similar patterns before they can be exploited in production environments.