Q: Given the following code slice:
```
1 static ssize_t disable_show(struct device *dev,
5 	struct usb_device *hdev = to_usb_device(dev->parent->parent);
6 	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
7 	struct usb_interface *intf = to_usb_interface(hub->intfdev);```
which has a CWE-476 vulnerability at line:
```
7 	struct usb_interface *intf = to_usb_interface(hub->intfdev);
```
Please analyze the root cause of the vulnerability.