# CVE-2025-40092: usb: gadget: f_ncm: Refactor bind path to use __free()

> A NULL pointer dereference in the Linux kernel USB NCM gadget driver allows local attackers to cause a system crash via bind/unbind cycles.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Oct 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-40092, DEBIAN-CVE-2025-40092, GHSA-68rx-wr32-vgh2, ROOT-OS-DEBIAN-11-CVE-2025-40092, ROOT-OS-UBUNTU-2204-CVE-2025-40092, ROOT-OS-UBUNTU-2404-CVE-2025-40092, UBUNTU-CVE-2025-40092

## What is CVE-2025-40092?

CVE-2025-40092 is a high-severity vulnerability in Linux, published on 30 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: f_ncm: Refactor bind path to use __free()

After an bind/unbind cycle, the ncm->notify_req is left stale. If a
subsequent bind fails, the unified error label attempts to free this
stale request, leading to a NULL pointer dereference when accessing
ep->ops->free_request.

Refactor the error handling in the bind path to use the __free()
automatic cleanup mechanism.

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020
Call trace:
 usb_ep_free_request+0x2c/0xec
 ncm_bind+0x39c/0x3dc
 usb_add_function+0xcc/0x1f0
 configfs_composite_bind+0x468/0x588
 gadget_bind_driver+0x104/0x270
 really_probe+0x190/0x374
 __driver_probe_device+0xa0/0x12c
 driver_probe_device+0x3c/0x218
 __device_attach_driver+0x14c/0x188
 bus_for_each_drv+0x10c/0x168
 __device_attach+0xfc/0x198
 device_initial_probe+0x14/0x24
 bus_probe_device+0x94/0x11c
 device_add+0x268/0x48c
 usb_add_gadget+0x198/0x28c
 dwc3_gadget_init+0x700/0x858
 __dwc3_set_mode+0x3cc/0x664
 process_scheduled_works+0x1d8/0x488
 worker_thread+0x244/0x334
 kthread+0x114/0x1bc
 ret_from_fork+0x10/0x20

## Which versions are affected by CVE-2025-40092?


## How do I fix CVE-2025-40092?

Apply the vendor's patch.

## Is CVE-2025-40092 being exploited?

There is no known exploitation of CVE-2025-40092 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-40092 and fix it if it is affected.

What it is: CVE-2025-40092 is a high-severity vulnerability in Linux, published on 30 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-40092 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-40092/ (Markdown: https://insights.sbomify.com/CVE-2025-40092/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-40092
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-40092
- OSV: https://osv.dev/vulnerability/CVE-2025-40092

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-40092/
Summaries are generated and may contain mistakes; the official description above is the record.