CVE-2026-57096 in Windows
Summary
by MITRE • 07/14/2026
Heap-based buffer overflow in Windows Routing and Remote Access Service (RRAS) allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 07/15/2026
The heap-based buffer overflow vulnerability in Windows Routing and Remote Access Service represents a critical security flaw that enables privilege escalation through local exploitation. This vulnerability specifically affects the RRAS component which handles network routing and remote access functionality within Windows operating systems. The issue stems from improper input validation within the heap memory management routines of the service, creating an exploitable condition where crafted input data can overwrite adjacent heap memory regions. The vulnerability is particularly concerning because it requires only local authentication to exploit, making it accessible to any user with legitimate login credentials on the target system.
The technical implementation of this flaw involves the RRAS service processing certain network configuration parameters that are not properly bounds-checked before being copied into allocated heap buffers. When malicious input exceeds the allocated buffer size, it overflows into adjacent memory locations, potentially corrupting critical data structures or executable code. This heap corruption can be leveraged to overwrite function pointers, return addresses, or other control data that governs program execution flow. The vulnerability aligns with CWE-121 which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to write beyond allocated memory boundaries.
From an operational perspective, this vulnerability presents a significant risk to organizations that rely on Windows RRAS for network connectivity and remote access services. Attackers who gain local access through legitimate means such as user accounts or service credentials can exploit this flaw to elevate their privileges from standard user level to SYSTEM level, effectively gaining complete control over the compromised system. The attack vector is particularly dangerous because it does not require network access or specialized tools beyond a local login session, making it an attractive target for insider threats or attackers who have already gained initial foothold through other means.
The impact extends beyond simple privilege escalation as the compromised system can then be used as a pivot point for lateral movement within the network infrastructure. An attacker with SYSTEM privileges can access sensitive network resources, modify routing configurations to redirect traffic, or establish persistent backdoors that maintain access even after initial compromise is detected. This vulnerability also aligns with ATT&CK technique T1068 which covers privilege escalation through local exploits and T1566 which encompasses social engineering attacks that may lead to local system compromise.
Mitigation strategies should include immediate deployment of Microsoft security patches that address the heap overflow condition in RRAS components, along with implementing least privilege principles for user accounts that require access to routing services. Network segmentation and monitoring should be enhanced to detect anomalous behavior patterns associated with privilege escalation attempts. System administrators should disable unnecessary RRAS functionality when not actively required and implement comprehensive logging of routing service activities. Additionally, regular security assessments should verify that all Windows systems have current updates applied and that vulnerable services are properly configured with minimal required privileges to reduce potential impact if exploitation occurs.
The vulnerability demonstrates the critical importance of proper memory management practices in system-level services and highlights how seemingly minor input validation flaws can result in severe privilege escalation capabilities. Organizations should implement robust security testing procedures including fuzzing and memory corruption analysis to identify similar conditions in other network services and applications. Regular security training for system administrators on recognizing and responding to local privilege escalation attempts remains essential for maintaining overall network security posture against such sophisticated attack vectors.