{"id":"CVE-2026-10663","title":"In Zephyr's experimental USB host stack (CONFIG_USB_HOST_STACK), usbh_device_disconnect() (subsys/usb/host/usbh_device.c) freed the root usb_device slab object without clearing the cached pointer ctx->root","summary":"In Zephyr's experimental USB host stack (CONFIG_USB_HOST_STACK), usbh_device_disconnect() (subsys/usb/host/usbh_device.c) freed the root usb_device slab object without clearing the cached pointer ctx->root. The bus removal handler dev_re…","severity":"medium","cvss":6.1,"cvssVector":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","cwe":["CWE-416"],"published":"2026-07-12","updated":"2026-07-12","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-10663","references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/4b87a8f161a44cb19505fa97db7cf72f64d49165","label":"vulnerabilities@zephyrproject.org"},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-26q8-xjq3-f5p6","label":"vulnerabilities@zephyrproject.org"}],"tags":["nvd"],"ingestedAt":"2026-07-12T17:20:29.543Z","epss":0.00236,"epssPercentile":0.14937,"slug":"CVE-2026-10663","body":"## Overview\n\nIn Zephyr's experimental USB host stack (CONFIG_USB_HOST_STACK), usbh_device_disconnect() (subsys/usb/host/usbh_device.c) freed the root usb_device slab object without clearing the cached pointer ctx->root. The bus removal handler dev_removed_handler() (subsys/usb/host/usbh_core.c) decides what to tear down solely from ctx->root, checking only that it is non-NULL.\n\nBecause UHC controller drivers (e.g. uhc_max3421e, uhc_mcux_common) synthesize UHC_EVT_DEV_REMOVED directly from physical bus line state with no debounce or state guard, an attacker with physical USB access (or a rogue device that bounces its connection) can deliver a second device-removed event after a root device disconnect. The handler then re-enters usbh_device_disconnect() with the dangling pointer, locking a mutex inside the freed object (use-after-free), removing the freed node from the device list, and calling k_mem_slab_free() on the already-freed block (double-free). If the slab block has been reissued to a newly attached device in between, this corrupts a live object.\n\nImpact is denial of service (crash) and memory corruption; the attack vector is physical/local. The flaw was introduced in v4.4.0 by the connect/disconnect refactor and is fixed by clearing ctx->root in usbh_device_disconnect() before freeing.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":34,"depthScoreParts":{"impact":33.6,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}