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Harman Mgu21 FirmwareOperating system · Samsung

CVE-2025-3885

MEDIUM · 6.5 CVSS v3.1 Published 2025-05-22
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
70/100
Remediation priority · Elevated
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

The Harman Becker MGU21 infotainment system uses a BCM89359 chipset with a Bluetooth stack that fails to properly validate incoming Bluetooth frames. An unauthenticated, network-adjacent attacker within Bluetooth range can send malformed frames that trigger a denial-of-service condition, causing the Bluetooth functionality or entire system to become unresponsive.

MitigationApply vendor-supplied firmware updates from Harman Becker when available; until then, limit Bluetooth exposure by disabling the feature in high-security environments or restricting physical access to the vehicle's infotainment system.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Harman Mgu21 FirmwareOperating system
Affected:= mgu21_22-07

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the infotainment system model
    Access the vehicle's infotainment system settings and locate the system information or diagnostics menu. Look for the model designation 'MGU21' or 'Harman Becker MGU21' in the device information.
    Affected if The system is not a Harman Becker MGU21 unit, the vulnerability does not apply.
  2. Verify the BCM89359 chipset
    In the infotainment system's diagnostics or hardware information section, check for the chipset specification. The vulnerability is specific to systems using the BCM89359 Bluetooth chipset.
    Affected if The system does not use the BCM89359 chipset, it is not affected by this specific vulnerability.
  3. Check the firmware version
    Navigate to the infotainment system's settings, typically under 'System', 'About', or 'Software Information' menu. Locate the firmware version string and compare it to 'mgu21_22-07'.
    Affected if The firmware version is exactly mgu21_22-07, the system is running the affected version.
  4. Confirm Bluetooth is enabled
    Access the Bluetooth settings menu on the infotainment system. Verify whether the Bluetooth radio is currently turned on or activated.
    Affected if Bluetooth is disabled or turned off, the attack surface is not exposed even on affected firmware versions.

A user is affected if their system is a Harman Becker MGU21 with BCM89359 chipset, running firmware version mgu21_22-07, with Bluetooth enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor-supplied firmware updates from Harman Becker when available; until then, limit Bluetooth exposure by disabling the feature in high-security environments or restricting physical access to the vehicle's infotainment system.

Fix this in Harman Mgu21 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,970
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-3885 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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