title: Buffer overflow on HUB descriptor in Azure RTOS USBX
description: Azure RTOS USBX is a USB host, device, and on-the-go (OTG) embedded stack. In versions prior to 6.1.10, an attacker can cause a buffer overflow by providing the Azure RTOS USBX host stack a HUB descriptor with `bNbPorts` set to a value greater than `UX_MAX_TT` which defaults to 8. For a `bNbPorts` value of 255, the implementation of `ux_host_class_hub_descriptor_get` function will modify the contents of `hub` -> `ux_host_class_hub_device` -> `ux_device_hub_tt` array violating the end boundary by 255 - `UX_MAX_TT` items. The USB host stack needs to validate the number of ports reported by the hub, and if the value is larger than UX_MAX_TT, USB stack needs to reject the request. This fix has been included in USBX release 6.1.10.
problem types: CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
affected:
{
product: usbx
vendor: azure-rtos
versions:
status: affected, version: < 6.1.10
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: NONE
baseScore: 7.5
baseSeverity: HIGH
confidentialityImpact: NONE
integrityImpact: HIGH
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
version: 3.1
]