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.
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.