CVE-2025-49757 in Windows
Summary
by MITRE • 08/12/2025
Heap-based buffer overflow in Windows Routing and Remote Access Service (RRAS) allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 11/21/2025
The vulnerability identified as CVE-2025-49757 represents a critical heap-based buffer overflow within the Windows Routing and Remote Access Service component that enables remote code execution by unauthorized attackers. This flaw exists in the RRAS functionality that manages network routing and remote access capabilities across Windows operating systems. The vulnerability manifests when the service processes specific network packets or configuration data that exceeds allocated memory boundaries, creating conditions where attacker-controlled data can overwrite adjacent memory locations in the heap allocation space.
The technical nature of this vulnerability stems from inadequate bounds checking within the RRAS implementation, specifically in how it handles incoming network traffic or configuration parameters. When legitimate network requests containing malformed data reach the RRAS service, the insufficient input validation causes the heap memory management to allocate insufficient space for the data, leading to overflow conditions. This memory corruption can be exploited to overwrite critical function pointers, return addresses, or other control data structures that govern program execution flow. The heap-based nature of the vulnerability means that attackers can manipulate memory layout to achieve arbitrary code execution, making this particularly dangerous as it can be leveraged from remote network locations without requiring local system access or authentication.
The operational impact of CVE-2025-49757 extends significantly across enterprise network environments where Windows RRAS services are deployed, including remote access servers, VPN gateways, and network infrastructure devices. Attackers can exploit this vulnerability to gain unauthorized access to systems running affected RRAS configurations, potentially establishing persistent backdoors, escalating privileges, or conducting lateral movement within network perimeters. The remote exploit capability eliminates the need for physical access or local credentials, making this vulnerability particularly attractive to threat actors targeting corporate networks. Organizations with RRAS services enabled on exposed network interfaces face immediate risk of compromise, especially in environments where these services are not properly isolated or secured through network segmentation controls.
Security professionals should prioritize immediate mitigation efforts including applying Microsoft security patches as they become available, implementing network segmentation to isolate RRAS services from untrusted networks, and monitoring for suspicious network activity patterns that might indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1071.004 for application layer protocol usage and T1059.001 for command and scripting interpreter, as exploitation typically involves crafting malicious network traffic to trigger the buffer overflow and subsequently executing malicious code. Organizations should also consider implementing intrusion detection systems with signature matching capabilities for known exploitation patterns and conducting comprehensive network audits to identify all systems running RRAS services that may be vulnerable to this heap overflow condition.
This vulnerability demonstrates the critical importance of proper memory management practices and input validation in network service implementations, particularly those handling untrusted network data. The CWE mapping for this issue would fall under CWE-121 heap-based buffer overflow, which is classified as a high-severity weakness in software security. Organizations should also consider implementing additional defensive measures such as address space layout randomization, data execution prevention, and regular security assessments of network infrastructure services to reduce the attack surface and improve overall resilience against similar memory corruption vulnerabilities.