Zephyr Project up to 4.4.x USB Host usbh_device.c usbh_device_init null pointer dereference

Summaryinfo

A vulnerability classified as critical was found in Zephyr Project Zephyr up to 4.4.x. This issue affects the function usbh_device_init of the file subsys/usb/host/usbh_device.c of the component USB Host. Executing a manipulation can lead to null pointer dereference. This vulnerability is handled as CVE-2026-90587. It is possible to launch the attack on the local host. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in Zephyr Project Zephyr up to 4.4.x and classified as critical. This vulnerability affects the function usbh_device_init of the file subsys/usb/host/usbh_device.c of the component USB Host. The manipulation with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. The product dereferences a pointer that it expects to be valid but is NULL. As an impact it is known to affect availability. CVE summarizes:

usbh_device_init() in subsys/usb/host/usbh_device.c rejects a device whose device descriptor advertises bNumConfigurations == 0, but it only logs the error and jumps to the cleanup label without setting the return code. At that point the local err is still 0 from the preceding successful descriptor read, so the function returns success while having skipped usbh_device_set_configuration() — the only place udev->cfg_desc is allocated. The device structure is zero-initialised by usbh_device_alloc(), so udev->cfg_desc remains NULL. usbh_device_connect() treats the zero return as a successful enumeration and calls usbh_class_probe_device(), which starts its descriptor walk from udev->cfg_desc. usbh_desc_get_next_function() passes that NULL pointer to usbh_desc_is_valid(), whose only guard compares the caller-supplied size, so head->bLength is read through a NULL pointer. The condition is triggered entirely by the attached peripheral: attaching a USB device (or any USB gadget emulating one) that reports bNumConfigurations = 0 reaches the defect directly from the UHC_EVT_DEV_CONNECTED_FS/_HS event handler in subsys/usb/host/usbh_core.c, with no authentication and no user interaction beyond the physical attachment. On targets where page zero is unmapped or CONFIG_NULL_POINTER_EXCEPTION_DETECTION is enabled this raises a fatal exception in the USB host thread, denying service to the host. Where address zero is readable, the descriptor walker instead parses low memory as a descriptor chain and can dispatch a class probe() with attacker-influenced values, causing further out-of-bounds reads through the still-NULL udev->cfg_desc in usbh_desc_get_iface(). No attacker-controlled write was identified, so the impact is availability plus a bounded out-of-bounds read. Note that CONFIG_USB_HOST_STACK is marked experimental.

The advisory is available at github.com. This vulnerability was named CVE-2026-90587 since 09/12/2026. The exploitation appears to be easy. Local access is required to approach this attack. Technical details are known, but there is no available exploit.

Upgrading to version 4.5.0 eliminates this vulnerability.

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Productinfo

Type

• Project Management Software

Vendor

• Zephyr Project

Name

• Zephyr

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4

CPE 2.3info

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CPE 2.2info

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Entryinfo

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