CVE-2025-49668: Heap-Based Buffer Overflow in Windows RRAS Resulting in Potential System Compromise

Overview

The vulnerability identified as CVE-2025-49668 is a grave security concern that affects the Windows Routing and Remote Access Service (RRAS). This vulnerability, which is a heap-based buffer overflow, enables unauthorized attackers to execute code over a network. Given the critical role that RRAS plays in facilitating network traffic for businesses and organizations, this vulnerability could potentially affect millions of systems worldwide. As such, it is of high importance for system administrators and cybersecurity professionals to understand the nature of this vulnerability, its potential impacts, and how it can be mitigated.

Vulnerability Summary

CVE ID: CVE-2025-49668
Severity: High (CVSS Score 8.8)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise and data leakage

Affected Products

Product | Affected Versions

Windows RRAS | All versions prior to the vendor patch

How the Exploit Works

This exploit takes advantage of a heap-based buffer overflow in Windows RRAS. This type of vulnerability occurs when an application writes more data to a buffer located on the heap than what is actually allocated for that buffer. This excess data then overflows into adjacent memory spaces, corrupting or overwriting the data they were holding. In this case, an attacker could craft a specific packet that, when processed by RRAS, would cause such an overflow, allowing the attacker to execute arbitrary code on the target system.

Conceptual Example Code

While a full example of a crafted packet is beyond the scope of this article, the following pseudo code illustrates the basic concept:

// Pseudo code for heap overflow exploit
buffer = allocate_buffer(512);
malicious_payload = generate_payload(1024); // Payload larger than allocated buffer
copy_to_buffer(buffer, malicious_payload);
send_packet(buffer);

In this simplified example, a buffer is allocated with a size of 512 bytes. However, a malicious payload of 1024 bytes is generated and copied into the buffer, causing an overflow. This overflow can overwrite critical data in the heap or even allow the execution of the attacker’s code when the overflowing data is written to a memory location that holds executable code or pointers to such code.
This vulnerability is a serious threat to the integrity and security of systems using affected versions of Windows RRAS. It is highly recommended for all users to apply the vendor-supplied patch immediately. If the patch cannot be applied immediately, a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) can be used as a temporary mitigation measure.