ZephyrProject Zephyr up to 4.4.1 USB Host Stack usbh_device.c usbh_device_set_configuration cfg_desc double free

Summaryinfo

A vulnerability, which was classified as very critical, was found in ZephyrProject Zephyr up to 4.4.1. The affected element is the function usbh_device_set_configuration of the file subsys/usb/host/usbh_device.c of the component USB Host Stack. Executing a manipulation of the argument cfg_desc can lead to double free. This vulnerability is tracked as CVE-2026-17050. The attack is restricted to local execution. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability has been found in ZephyrProject Zephyr up to 4.4.1 and classified as very critical. This vulnerability affects the function usbh_device_set_configuration of the file subsys/usb/host/usbh_device.c of the component USB Host Stack. The manipulation of the argument cfg_desc with an unknown input leads to a double free vulnerability. The CWE definition for the vulnerability is CWE-415. The product calls free() twice on the same memory address, potentially leading to modification of unexpected memory locations. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

The experimental USB host stack allocates a per-device configuration-descriptor buffer, udev->cfg_desc, from the dedicated usb_device_heap in usbh_device_set_configuration() (subsys/usb/host/usbh_device.c). On three failure paths — a failed full-length GET_DESCRIPTOR(CONFIGURATION) read, a mismatch between the short and full descriptor reads, and a rejected descriptor in parse_configuration_descriptor() — the buffer was released with k_heap_free() but the pointer was left dangling. The cleanup in usbh_device_free() is guarded only by if (udev->cfg_desc != NULL), so it frees the same block a second time. The path is driven entirely by the attached peripheral: usbh_device_connect() calls usbh_device_init(), which ends in usbh_device_set_configuration(), and on failure usbh_device_connect() calls usbh_device_free(). On v4.4.x this happens during the same enumeration, with no unplug required; on v4.1.0–v4.3.x the second free instead arrives via dev_removed_handler()/dev_connected_handler() in subsys/usb/host/usbh_core.c, so it requires a removal or duplicate-connect event after the failed enumeration — a sequence the attached device fully controls. A malicious or malformed USB device only has to answer the first 9-byte configuration-descriptor request with a well-formed header and then fail any of the three checks, for example by returning a full descriptor whose interface count disagrees with bNumInterfaces, or by answering the second read with different bytes. The result is a double free on usb_device_heap. On builds where lib/heap hardening is active (the current default CONFIG_SYS_HEAP_HARDENING_BASIC), sys_heap_free() detects the already-free chunk and calls k_panic(), giving a deterministic, peripheral-triggered denial of service of the USB host. On builds without that detection — earlier releases, or CONFIG_SYS_HEAP_HARDENING_NONE — the second free manipulates a chunk already on the free list, corrupting the heap's free list so that later allocations can return overlapping or invalid blocks. Exploitation beyond denial of service is bounded by the fact that usb_device_heap is a small dedicated heap (CONFIG_USBH_USB_DEVICE_HEAP, default 1024 bytes) whose only client is this descriptor buffer, and by CONFIG_USB_HOST_STACK being marked experimental and disabled by default. The fix sets udev->cfg_desc = NULL after every k_heap_free(), making the cleanup guard sound.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-17050 since 07/24/2026. The exploitation appears to be easy. The attack needs to be approached locally. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/21/2026).

Upgrading to version 4.4.2 eliminates this vulnerability. Applying the patch d46a8c1f8fb65e1f80b44bd651a6dafea747602e is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Project Management Software

Vendor

• ZephyrProject

Name

• Zephyr

Version

• 4.4.0
• 4.4.1

CPE 2.3info

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CPE 2.2info

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