CVE-2025-49694: Null Pointer Dereference Vulnerability in Microsoft Brokering File System

Overview

The CVE-2025-49694 is a critical security vulnerability in the Microsoft Brokering File System. This vulnerability allows an authorized attacker to exploit a null pointer dereference, leading to an elevation of privileges on a local level. As a cybersecurity issue, it poses a serious risk to all users, particularly those operating in enterprise environments where sensitive data might be accessible. This vulnerability, if left unpatched, could lead to potential system compromise or data leakage, which underscores the importance of immediate action and mitigation.

Vulnerability Summary

CVE ID: CVE-2025-49694
Severity: High (CVSS: 7.8)
Attack Vector: Local
Privileges Required: Low
User Interaction: Required
Impact: Elevation of privileges, potential system compromise, or data leakage

Affected Products

Product | Affected Versions

Microsoft Brokering File System | All current versions

How the Exploit Works

The exploit works by an authenticated attacker sending a specially crafted file to a vulnerable version of the Microsoft Brokering File System. This file triggers a null pointer dereference that can be leveraged by the attacker to execute arbitrary code with elevated privileges on the affected system, potentially leading to a full system compromise or data leakage.

Conceptual Example Code

Below is a conceptual example of how the vulnerability might be exploited. Note that this is pseudocode and it’s only intended to demonstrate the exploit conceptually:

#!/usr/bin/env python
import requests
import json
# Prepare the malicious payload
malicious_payload = {
"file": {
"name": "exploit.txt",
"content": "NULL_POINTER_DEREFERENCE_TRIGGER"
}
}
# Send the malicious payload to the vulnerable system
response = requests.post(
"http://target.example.com/vulnerable/endpoint",
headers={"Content-Type": "application/json"},
data=json.dumps(malicious_payload)
)
# Check the response
if response.status_code == 200:
print("Exploit successful!")
else:
print("Exploit failed.")

The above code demonstrates how an attacker might craft and send a malicious file to the vulnerable endpoint. If the exploit is successful, the attacker would be able to execute arbitrary code with elevated privileges on the target system.
In order to mitigate this vulnerability, it is advised to apply the vendor’s security patch as soon as possible or use a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) as a temporary measure.