ZephyrProject Zephyr up to 4.4.1 IT82xx2 USB Device-Controller Driver udc_it82xx2.c work_handler_out use after free

Summaryinfo

A vulnerability classified as very critical has been found in ZephyrProject Zephyr up to 4.4.1. Affected by this vulnerability is the function work_handler_out of the file drivers/usb/udc/udc_it82xx2.c of the component IT82xx2 USB Device-Controller Driver. Performing a manipulation results in use after free. This vulnerability is cataloged as CVE-2026-16147. The attack must be initiated from a local position. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as very critical, was found in ZephyrProject Zephyr up to 4.4.1. This affects the function work_handler_out of the file drivers/usb/udc/udc_it82xx2.c of the component IT82xx2 USB Device-Controller Driver. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

The ITE IT82xx2 USB device-controller driver (drivers/usb/udc/udc_it82xx2.c) mishandles multi-packet OUT transfers on non-control endpoints. In work_handler_out() the active transfer buffer is obtained with udc_buf_peek() (which does not dequeue it); when a full max-packet-size packet arrives but the buffer still has tailroom (the transfer is not yet complete), the pre-fix code both re-arms the endpoint to keep filling that same buf via work_handler_xfer_continue() and simultaneously hands the same, still-being-filled buffer to the upper stack with udc_submit_ep_event(). Because udc_submit_ep_event() transfers ownership of the buffer to the USB device stack (usbd_event_carrier() appends &buf->node to uds_ctx->ep_events, after which the class handler processes and net_buf_unref()s it), the driver continues to DMA subsequent host-controlled OUT packets into a buffer the upper stack may already have freed and recycled — a use-after-free write. In addition, since the buffer was never dequeued, the completing packet runs udc_buf_get() on the same object and submits it a second time, appending &buf->node to the event slist twice (singly-linked-list corruption) and causing a double net_buf_unref(). The IT82xx2 is a USB peripheral controller, so the untrusted USB host controls OUT-transfer packetization and can force this path against any non-control OUT endpoint whose queued buffer exceeds one packet — an ordinary bulk/interrupt pattern. The driver and USB device stack run in kernel context above the external host, giving the host a device-side kernel heap-corruption primitive: a reliable denial of service and, because the written bytes are attacker-controlled, plausible corruption of adjacent net_buf pool memory. The vector is physical (USB attach). The fix defers submission until the buffer is completely filled and lets xfer_work_handler() drive continuation, so each OUT buffer is submitted to the upper stack exactly once.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-16147 since 07/17/2026. The exploitability is told to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/14/2026).

Upgrading to version 4.4.2 eliminates this vulnerability. Applying the patch 2abc3088a6598579cf322452801a13cb0ec57b0e is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best 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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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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