CVE-2025-20672: Out-of-bounds Write Vulnerability in Bluetooth Driver

Overview

CVE-2025-20672 is a serious vulnerability present in the Bluetooth driver that could potentially be exploited to escalate privileges on the local system, leading to unauthorized system control or data leakage. The vulnerability is due to an incorrect bounds check, which allows an out-of-bounds write. This could be exploited by a malicious user with execution privileges, with no user interaction required for exploitation. Anyone using a system with the affected Bluetooth driver is at risk. Given the pervasive use of Bluetooth, this vulnerability has the potential to affect a significant number of users, and it is important to take immediate steps to mitigate the risk.

Vulnerability Summary

CVE ID: CVE-2025-20672
Severity: Critical (CVSS Score 9.8)
Attack Vector: Local
Privileges Required: User
User Interaction: None
Impact: Local privilege escalation, potential system compromise, and data leakage

Affected Products

Product | Affected Versions

Bluetooth Driver | All versions prior to patch WCNCR00412257

How the Exploit Works

The exploit works by taking advantage of the incorrect bounds check in the Bluetooth driver. By sending specially crafted data to the driver, an attacker can cause an out-of-bounds write, which could potentially overwrite important data or code in memory. This could lead to unexpected behavior, including the execution of arbitrary code with user privileges, which could in turn lead to local escalation of privilege.

Conceptual Example Code

While specific exploit code is not provided, conceptually, the exploit may involve sending a large amount of data to the Bluetooth driver, in a manner similar to a buffer overflow attack. The pseudocode below illustrates this concept:

char buffer[1024];
memset(buffer, 'A', 2048);  // Fill buffer with more data than it can hold
write_to_bluetooth_driver(buffer, 2048);  // Trigger out-of-bounds write

In this example, the `write_to_bluetooth_driver` function would represent the vulnerable function in the Bluetooth driver that performs the incorrect bounds check. The buffer is filled with more data than it can hold, causing an out-of-bounds write when the data is written to the driver.

Mitigation Guidance

Users are strongly advised to apply the patch identified as WCNCR00412257. Until the patch can be applied, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) may provide temporary mitigation against potential attacks. Regularly updating and patching systems is the best way to protect against vulnerabilities such as CVE-2025-20672.