Body Background
TrendAI™ Zero Day Initiative™ Logo

(0Day) Harman Becker MGU21 Bluetooth Improper Input Validation Denial-of-Service Vulnerability

April 23rd, 2025

Vulnerability Details

This vulnerability allows network-adjacent attackers to create a denial-of-service condition on affected installations of Harman Becker MGU21 devices. Authentication is not required to exploit this vulnerability.

The specific flaw exists within the Bluetooth stack of the BCM89359 chipset. The issue results from the lack of proper validation of Bluetooth frames. An attacker can leverage this vulnerability to create a denial-of-service condition on the system.

Additional Details

06/12/24 – ZDI reported the vulnerability to the vendor
06/13/24 – the vendor acknowledged the receipt of the report
09/30/24 - ZDI asked for updates
10/01/24 – The vendor communicated that the reported behaviour will not be fixed by a third party
10/02/24 – ZDI informed the vendor of the intention to publish the case as a zero-day advisory


Disclosure Timeline

  • 2024-06-12 - Vulnerability reported to vendor
  • 2025-04-23 - Coordinated public release of advisory
  • 2025-04-23 - Advisory Updated

Credit

Aaron Luo, Gloria Chen, Omar Yang, Spencer Hsieh, and Vit Sembera of VicOne

Back to Advisories

Hero Background

Stand at the front line of proactive security

Trend ZDI connects the experts who discover, remediate, and defend.
Add your voice to the work that pushes attackers back.