- Description
- 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_removed_handler() (subsys/usb/host/usbh_core.c) decides what to tear down solely from ctx->root, checking only that it is non-NULL. Because 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. Impact 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.
- Source
- vulnerabilities@zephyrproject.org
- NVD status
- Analyzed
- Products
- zephyr
CVSS 3.1
- Type
- Secondary
- Base score
- 6.1
- Impact score
- 5.2
- Exploitability score
- 0.9
- Vector string
- CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
- Severity
- MEDIUM
- vulnerabilities@zephyrproject.org
- CWE-416
- Hype score
- Not currently trending
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