5.5
MEDIUM CVSS 3.1
CVE-2021-46986
"Linux Kernel USB DWC3 Endpoint Use-after-Free"
Description

In the Linux kernel, the following vulnerability has been resolved: usb: dwc3: gadget: Free gadget structure only after freeing endpoints As part of commit e81a7018d93a ("usb: dwc3: allocate gadget structure dynamically") the dwc3_gadget_release() was added which will free the dwc->gadget structure upon the device's removal when usb_del_gadget_udc() is called in dwc3_gadget_exit(). However, simply freeing the gadget results a dangling pointer situation: the endpoints created in dwc3_gadget_init_endpoints() have their dep->endpoint.ep_list members chained off the list_head anchored at dwc->gadget->ep_list. Thus when dwc->gadget is freed, the first dwc3_ep in the list now has a dangling prev pointer and likewise for the next pointer of the dwc3_ep at the tail of the list. The dwc3_gadget_free_endpoints() that follows will result in a use-after-free when it calls list_del(). This was caught by enabling KASAN and performing a driver unbind. The recent commit 568262bf5492 ("usb: dwc3: core: Add shutdown callback for dwc3") also exposes this as a panic during shutdown. There are a few possibilities to fix this. One could be to perform a list_del() of the gadget->ep_list itself which removes it from the rest of the dwc3_ep chain. Another approach is what this patch does, by splitting up the usb_del_gadget_udc() call into its separate "del" and "put" components. This allows dwc3_gadget_free_endpoints() to be called before the gadget is finally freed with usb_put_gadget().

INFO

Published Date :

Feb. 28, 2024, 9:15 a.m.

Last Modified :

Dec. 31, 2024, 4:14 p.m.

Remotely Exploit :

No

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products

The following products are affected by CVE-2021-46986 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 MEDIUM [email protected]
Solution
This information is provided by the 3rd party feeds.
  • There is no known solution at this time.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-46986 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-46986 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-46986 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-46986 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • Initial Analysis by [email protected]

    Dec. 31, 2024

    Action Type Old Value New Value
    Added CVSS V3.1 NIST AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
    Added CWE NIST CWE-416
    Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.10 up to (excluding) 5.10.38 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.11.22 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.12 up to (excluding) 5.12.5 *cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*
    Changed Reference Type https://git.kernel.org/stable/c/1ea775021282d90e1d08d696b7ab54aa75d688e5 No Types Assigned https://git.kernel.org/stable/c/1ea775021282d90e1d08d696b7ab54aa75d688e5 Patch
    Changed Reference Type https://git.kernel.org/stable/c/1ea775021282d90e1d08d696b7ab54aa75d688e5 No Types Assigned https://git.kernel.org/stable/c/1ea775021282d90e1d08d696b7ab54aa75d688e5 Patch
    Changed Reference Type https://git.kernel.org/stable/c/b4b8e9601d7ee8806d2687f081a42485d27674a1 No Types Assigned https://git.kernel.org/stable/c/b4b8e9601d7ee8806d2687f081a42485d27674a1 Patch
    Changed Reference Type https://git.kernel.org/stable/c/b4b8e9601d7ee8806d2687f081a42485d27674a1 No Types Assigned https://git.kernel.org/stable/c/b4b8e9601d7ee8806d2687f081a42485d27674a1 Patch
    Changed Reference Type https://git.kernel.org/stable/c/bb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139 No Types Assigned https://git.kernel.org/stable/c/bb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139 Patch
    Changed Reference Type https://git.kernel.org/stable/c/bb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139 No Types Assigned https://git.kernel.org/stable/c/bb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139 Patch
    Changed Reference Type https://git.kernel.org/stable/c/bc0cdd72493236fb72b390ad38ce581e353c143c No Types Assigned https://git.kernel.org/stable/c/bc0cdd72493236fb72b390ad38ce581e353c143c Patch
    Changed Reference Type https://git.kernel.org/stable/c/bc0cdd72493236fb72b390ad38ce581e353c143c No Types Assigned https://git.kernel.org/stable/c/bc0cdd72493236fb72b390ad38ce581e353c143c Patch
  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://git.kernel.org/stable/c/1ea775021282d90e1d08d696b7ab54aa75d688e5
    Added Reference https://git.kernel.org/stable/c/b4b8e9601d7ee8806d2687f081a42485d27674a1
    Added Reference https://git.kernel.org/stable/c/bb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139
    Added Reference https://git.kernel.org/stable/c/bc0cdd72493236fb72b390ad38ce581e353c143c
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    May. 28, 2024

    Action Type Old Value New Value
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Feb. 28, 2024

    Action Type Old Value New Value
    Added Description In the Linux kernel, the following vulnerability has been resolved: usb: dwc3: gadget: Free gadget structure only after freeing endpoints As part of commit e81a7018d93a ("usb: dwc3: allocate gadget structure dynamically") the dwc3_gadget_release() was added which will free the dwc->gadget structure upon the device's removal when usb_del_gadget_udc() is called in dwc3_gadget_exit(). However, simply freeing the gadget results a dangling pointer situation: the endpoints created in dwc3_gadget_init_endpoints() have their dep->endpoint.ep_list members chained off the list_head anchored at dwc->gadget->ep_list. Thus when dwc->gadget is freed, the first dwc3_ep in the list now has a dangling prev pointer and likewise for the next pointer of the dwc3_ep at the tail of the list. The dwc3_gadget_free_endpoints() that follows will result in a use-after-free when it calls list_del(). This was caught by enabling KASAN and performing a driver unbind. The recent commit 568262bf5492 ("usb: dwc3: core: Add shutdown callback for dwc3") also exposes this as a panic during shutdown. There are a few possibilities to fix this. One could be to perform a list_del() of the gadget->ep_list itself which removes it from the rest of the dwc3_ep chain. Another approach is what this patch does, by splitting up the usb_del_gadget_udc() call into its separate "del" and "put" components. This allows dwc3_gadget_free_endpoints() to be called before the gadget is finally freed with usb_put_gadget().
    Added Reference Linux https://git.kernel.org/stable/c/1ea775021282d90e1d08d696b7ab54aa75d688e5 [No types assigned]
    Added Reference Linux https://git.kernel.org/stable/c/bc0cdd72493236fb72b390ad38ce581e353c143c [No types assigned]
    Added Reference Linux https://git.kernel.org/stable/c/b4b8e9601d7ee8806d2687f081a42485d27674a1 [No types assigned]
    Added Reference Linux https://git.kernel.org/stable/c/bb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139 [No types assigned]
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 5.5
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact