CVE-2023-28909 in Volkswagen MIB3 Infotainment System MIB3 OI MQB
Summary
by MITRE • 06/28/2025
A specific flaw exists within the Bluetooth stack of the MIB3 unit. The issue results from the lack of proper validation of user-supplied data, which can result in an integer overflow when receiving fragmented HCI packets on a channel. An attacker can leverage this vulnerability to bypass the MTU check on a channel with enabled fragmentation. Consequently, this can lead to a buffer overflow in upper layer profiles, which can be used to obtain remote code execution. The vulnerability was originally discovered in Skoda Superb III car with MIB3 infotainment unit OEM part number 3V0035820. The list of affected MIB3 OEM part numbers is provided in the referenced resources.
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Analysis
by VulDB Data Team • 07/01/2025
The vulnerability identified as CVE-2023-28909 represents a critical security flaw within the Bluetooth stack of MIB3 infotainment units, specifically affecting vehicles in the Skoda Superb III lineup. This issue stems from insufficient validation of user-supplied data within the Bluetooth protocol implementation, creating a pathway for exploitation that can compromise the entire vehicle's infotainment system. The vulnerability manifests when the system receives fragmented HCI (Host Controller Interface) packets on a channel, where the lack of proper input validation leads to an integer overflow condition that bypasses normal MTU (Maximum Transmission Unit) checks. This flaw is particularly concerning as it exists within automotive systems where cybersecurity is paramount for both vehicle operation and occupant safety.
The technical implementation of this vulnerability involves the Bluetooth stack's handling of fragmented packets, where the system fails to properly validate the size and structure of incoming data segments. When fragmentation is enabled on a channel, the system should enforce strict MTU boundaries to prevent buffer overflows, but due to the integer overflow condition, these protections can be circumvented. This allows an attacker to craft malicious HCI packets that exceed normal buffer boundaries, leading to memory corruption in upper-layer Bluetooth profiles. The integer overflow occurs during the processing of packet fragmentation logic, where the system's arithmetic operations produce values that exceed the maximum representable integer, creating a condition that can be exploited to overwrite adjacent memory locations. This type of vulnerability aligns with CWE-190, Integer Overflow or Wraparound, which is classified as a fundamental weakness in data handling and validation.
The operational impact of CVE-2023-28909 extends beyond simple data corruption, as it creates a potential pathway for remote code execution within the vehicle's infotainment system. Attackers with access to the Bluetooth network can leverage this vulnerability to gain unauthorized control over the MIB3 unit, potentially accessing sensitive vehicle data or executing malicious code that could affect vehicle functionality. The exploitation requires minimal physical proximity or network access, making it particularly dangerous in automotive environments where Bluetooth connectivity is commonly used for hands-free calling, media streaming, and vehicle diagnostics. This vulnerability affects specific OEM part numbers including 3V0035820, indicating that the flaw is present in particular implementations of the MIB3 system, though similar issues may exist in other variants. The implications of such a vulnerability in automotive systems are significant, as they can potentially be used to compromise vehicle security, access personal data, or even affect vehicle operation through malicious code execution.
Mitigation strategies for CVE-2023-28909 should focus on both immediate remediation and long-term architectural improvements to prevent similar vulnerabilities. Vehicle manufacturers should implement firmware updates that properly validate packet sizes and implement robust input sanitization for all HCI packet processing. The fix should address the integer overflow condition by ensuring proper bounds checking and implementing defensive programming practices that prevent arithmetic operations from producing values that exceed system limits. Additionally, network segmentation and access controls should be implemented to limit Bluetooth connectivity to only necessary services and prevent unauthorized access to critical vehicle systems. The vulnerability demonstrates the importance of applying security principles such as the principle of least privilege and defense in depth, which are core concepts in the MITRE ATT&CK framework for enterprise security. Organizations should also consider implementing runtime monitoring and anomaly detection systems to identify potential exploitation attempts and provide early warning of security incidents. The affected MIB3 units require immediate patching through official manufacturer updates, as the vulnerability represents a significant risk to vehicle cybersecurity and could potentially be exploited to compromise vehicle safety systems.