{"id":"CVE-2021-46986","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: dwc3: gadget: Free gadget structure only after freeing endpoints\n\nAs part of commit e81a7018d93a (\"usb: dwc3: allocate gadget structure\ndynamically\") the dwc3_gadget_release() was added which will free\nthe dwc-\u003egadget structure upon the device's removal when\nusb_del_gadget_udc() is called in dwc3_gadget_exit().\n\nHowever, simply freeing the gadget results a dangling pointer\nsituation: the endpoints created in dwc3_gadget_init_endpoints()\nhave their dep-\u003eendpoint.ep_list members chained off the list_head\nanchored at dwc-\u003egadget-\u003eep_list.  Thus when dwc-\u003egadget is freed,\nthe first dwc3_ep in the list now has a dangling prev pointer and\nlikewise for the next pointer of the dwc3_ep at the tail of the list.\nThe dwc3_gadget_free_endpoints() that follows will result in a\nuse-after-free when it calls list_del().\n\nThis was caught by enabling KASAN and performing a driver unbind.\nThe recent commit 568262bf5492 (\"usb: dwc3: core: Add shutdown\ncallback for dwc3\") also exposes this as a panic during shutdown.\n\nThere are a few possibilities to fix this.  One could be to perform\na list_del() of the gadget-\u003eep_list itself which removes it from\nthe rest of the dwc3_ep chain.\n\nAnother approach is what this patch does, by splitting up the\nusb_del_gadget_udc() call into its separate \"del\" and \"put\"\ncomponents.  This allows dwc3_gadget_free_endpoints() to be\ncalled before the gadget is finally freed with usb_put_gadget().","modified":"2026-03-14T11:18:52.639779Z","published":"2024-02-28T09:15:37.540Z","references":[{"type":"FIX","url":"https://git.kernel.org/stable/c/1ea775021282d90e1d08d696b7ab54aa75d688e5"},{"type":"FIX","url":"https://git.kernel.org/stable/c/b4b8e9601d7ee8806d2687f081a42485d27674a1"},{"type":"FIX","url":"https://git.kernel.org/stable/c/bb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139"},{"type":"FIX","url":"https://git.kernel.org/stable/c/bc0cdd72493236fb72b390ad38ce581e353c143c"}],"affected":[{"database_specific":{"unresolved_ranges":[{"events":[{"introduced":"5.10"},{"fixed":"5.10.38"}]},{"events":[{"introduced":"5.11"},{"fixed":"5.11.22"}]},{"events":[{"introduced":"5.12"},{"fixed":"5.12.5"}]},{"events":[{"introduced":"0"},{"last_affected":"5.13-rc1"}]}],"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-46986.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}