External risk intelligence

BYD Dilink Headunit Authentication Bypass Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2024-46442

This vulnerability affects an automotive head unit system. Such systems are embedded components within a vehicle, not typical internet-facing services, web applications, or gateways. They are designed for local interaction within the vehicle environment and are not intended to be exposed to the public internet in common deployments.

Halo Surface Signal: 1 out of 5 — much less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

An authentication bypass vulnerability has been identified in certain versions of the BYD Dilink Headunit System. This issue could potentially allow unauthorized access to the system if exploited. The main concern at this time is to confirm if this technology is used within our environment and assess any potential exposure.

Attackers can bypass login controls.
It affects automotive infotainment systems.
Confirm relevance and exposure to our business.

Attack Path

How an attacker could exploit the issue

An attacker could reach an unauthenticated state in the BYD Dilink Headunit System by repeatedly guessing credentials. This access would then allow the attacker to interact with a vulnerable component, potentially leading to a complete compromise of the system.

Network exposure required.
Brute-force password guessing.
Unauthenticated access to system.

Live Threat

Current exploitation, exposure, and threat context

A critical vulnerability in the BYD Dilink Headunit System could allow an unauthenticated attacker to bypass authentication. This could potentially lead to unauthorized access to the system's functionalities when the system is accessible over a network.

System authentication mechanisms.
Network access to the head unit.
Unauthorized system access.

Operational Fix

Recommended remediation, mitigation, and detection steps

This critical vulnerability in the BYD Dilink Headunit System impacts automotive systems. Initial triage should focus on identifying all deployed head unit systems, assessing their network exposure and business criticality within the vehicle's operational context, and then locating the accountable owner, likely within the automotive manufacturing or specific vehicle model support teams, to plan remediation based on risk.

Automotive systems owners must address this.
Verify network exposure and system criticality.
Plan for vendor-coordinated updates.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

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Frequently asked questions

What is the BYD Dilink Headunit System?

The BYD Dilink Headunit System is the integrated dashboard infotainment technology found in BYD vehicles. It manages various onboard features, including media playback, navigation, and vehicle settings. It functions as a central computing hub for the driver and passengers to interact with the car's digital environment, essentially acting as the primary interface between the user and the vehicle's internal software applications.

What does CWE-307 mean for CVE-2024-46442?

CWE-307 refers to the Improper Restriction of Excessive Authentication Attempts. In the context of CVE-2024-46442, this means the head unit lacks sufficient safeguards against brute-force attacks. Essentially, the system does not adequately limit or lock out login attempts, allowing an attacker to repeatedly guess credentials until they gain unauthorized access to the device's controls and data.

How does an attacker trigger this authentication bypass?

An attacker triggers this vulnerability by sending a high volume of login requests to the head unit to guess valid credentials. This attack path requires network connectivity to the system. Importantly, this bug is not triggered by standard, legitimate user interactions or normal vehicle operation; it specifically relies on the absence of rate-limiting mechanisms that would otherwise block repeated, rapid authentication failures.

Is this vulnerability a risk if my device is offline?

According to Halo Surface Signal, this vulnerability is very unlikely to pose a risk in typical deployments. Because the head unit is an embedded automotive component, it is designed for local, in-vehicle interaction rather than as an internet-facing service. The threat primarily concerns scenarios where the system is improperly exposed to a network, which is not how these units are intended to be used in everyday driving.

Do I need to take action if I use this technology?

If you are responsible for fleets or systems using this technology, start by inventorying your deployed head units. Verify whether any units are connected to external networks, which deviates from standard automotive operation. Once you have identified the affected devices and confirmed their network status, coordinate with your automotive vendor or vehicle support team to determine the official update path for patching the authentication mechanism.

References

github.com/zgsnj123/BYD_headunit_vuls/tree/main

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.