CVE-2025-30385: Critical Privilege Escalation Vulnerability in Windows Common Log File System Driver

Overview

CVE-2025-30385 is a significant vulnerability that could potentially affect a wide range of Windows users. This vulnerability exists in the Windows Common Log File System Driver, and it allows an authorized attacker to elevate privileges locally through a ‘use after free’ flaw. The implications of such a vulnerability are grave, as it could lead to unauthorized access to sensitive data or even total system compromise. Therefore, understanding and mitigating this vulnerability is crucial for businesses and individual users alike.

Vulnerability Summary

CVE ID: CVE-2025-30385
Severity: High (7.8 CVSS score)
Attack Vector: Local
Privileges Required: Low
User Interaction: None
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

Windows Common Log File System Driver | All versions prior to patch

How the Exploit Works

The CVE-2025-30385 vulnerability stems from a use-after-free flaw in the Windows Common Log File System Driver. In a use-after-free scenario, a piece of memory is used after it has been freed, leading to various adverse effects, including program crashes, incorrect computations, and in this case, privilege escalation.
An attacker who has local access to the system can exploit this flaw to corrupt memory and execute arbitrary code with elevated system privileges. This could potentially lead to complete system compromise or data leakage, depending on the attacker’s intentions.

Conceptual Example Code

While we won’t provide a direct exploit code, let’s visualize how an attacker might potentially exploit this vulnerability through pseudocode:

#include <windows.h>
int main() {
// Obtain a handle to the vulnerable driver
HANDLE hDriver = OpenDriver("\\\\.\\VulnerableDriver", GENERIC_READ | GENERIC_WRITE);
// Allocate memory for the buffer
char *buffer = (char *)malloc(BUFFER_SIZE);
// ... Fill the buffer with malicious data ...
// Send the buffer to the driver
DeviceIoControl(hDriver, IOCTL_VULNERABLE, buffer, BUFFER_SIZE, NULL, 0, NULL, NULL);
// Free the buffer
free(buffer);
// ... Later in the program ...
// Use the buffer after it has been freed, triggering the vulnerability
char c = buffer[0];
return 0;
}

In this hypothetical scenario, the attacker sends a malicious buffer to the vulnerable driver and then uses the buffer after it has been freed, triggering the use-after-free vulnerability and leading to potential privilege escalation.

Mitigation Guidance

The primary mitigation strategy for this vulnerability is to apply the vendor-provided patch. All users of the affected Windows Common Log File System Driver versions are strongly recommended to update their systems with this patch as soon as possible.
In case patching is not immediately possible, using a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) can provide temporary mitigation. These systems can detect and block known exploit attempts, providing a layer of security while the patching process is being implemented.