Vulnerability · Published May 22, 2025 · Assigned by zdi

CVE-2025-3885Harman Becker MGU21 Bluetooth Improper Input Validation Denial-of-Service Vulnerability

Medium 5.3

In plain English

A medium-severity improper input validation in MGU21 from Harman Becker. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities).

Severity (CVSS 3.0)5.3Medium

Exploit odds (30 days)0.3%top 78.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Harman Becker MGU21 Bluetooth Improper Input Validation Denial-of-Service Vulnerability. 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. Was ZDI-CAN-23942.

Affected products (as reported)

Vendor	Product	Versions
Harman Becker	MGU21	MGU21_22-07 firmware with BCM89359 wireless chipset; LMP Version: 5.0 (0x9); LMP Subversion: 0x420d

Weakness: CWE-20 · Vector: CVSS:3.0/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

ZDI-25-251 x_research-advisory