{"id":"CVE-2026-16147","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-16147","generatedAt":"2026-10-27T23:57:29.465Z","title":"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…","description":"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().\n\nBecause 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().\n\nThe 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.","published":"2026-09-14T20:16:39.000Z","lastModified":"2026-09-14T21:10:42.000Z","status":"Awaiting Analysis","sourceIdentifier":"vulnerabilities@zephyrproject.org","cvss":{"version":"3.1","score":6.8,"severity":"MEDIUM","vector":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-416"],"affected":[],"epss":{"score":0.00258,"percentile":0.17315,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.26%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/2abc3088a6598579cf322452801a13cb0ec57b0e","source":"vulnerabilities@zephyrproject.org"},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-3q4g-7w6j-8qfp","source":"vulnerabilities@zephyrproject.org"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-16147","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}