# CVE-2026-89739: usb: dwc3: gadget: Fix use-after-free in dwc3_gadget_free_endpoints due to race condition

> A race condition in the Linux kernel DWC3 USB gadget driver allows a use-after-free, potentially enabling local attackers to execute code or escalate privileges.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** BELL-CVE-2026-89739, DEBIAN-CVE-2026-89739, GHSA-5q8g-48x9-ppw2, UBUNTU-CVE-2026-89739

## What is CVE-2026-89739?

CVE-2026-89739 is an use after free vulnerability in Linux, published on 11 Sep 2026. 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: dwc3: gadget: Fix use-after-free in dwc3_gadget_free_endpoints due to race condition

In dwc3_gadget_init_endpoint, &dep->nostream_work is bound with
dwc3_nostream_work, and dwc3_gadget_endpoint_stream_event can queue
this delayed work on system_percpu_wq when a DEPEVT_STREAM_NOSTREAM
event is received.

If we remove the gadget, dwc3_gadget_free_endpoints makes cleanup and
the memory allocated for dep with kzalloc() is released by kfree(dep),
while the delayed work mentioned above may still be pending or
running. The sequence of operations that may lead to a UAF bug is as
follows:

CPU0                                      CPU1

                                          | dwc3_thread_interrupt
                                          | dwc3_endpoint_interrupt
                                          | dwc3_gadget_endpoint_stream_event
                                          | queue_delayed_work(system_percpu_wq,
                                          |                    &dep->nostream_work)
dwc3_gadget_free_endpoints                |
dwc3_free_trb_pool(dep)                   |
list_del(&dep->endpoint.ep_list)          |
dwc3_debugfs_remove_endpoint_dir(dep)     |
kfree(dep)                                |
// dep is freed                           |
                                          | dwc3_nostream_work
                                          | // use dep (use-after-free)

Fix it by canceling the delayed work before kfree(dep) in
dwc3_gadget_free_endpoints.

## Which versions are affected by CVE-2026-89739?


## How do I fix CVE-2026-89739?

Apply the vendor's patch.

## Is CVE-2026-89739 being exploited?

There is no known exploitation of CVE-2026-89739 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89739 and fix it if it is affected.

What it is: CVE-2026-89739 is an use after free vulnerability in Linux, published on 11 Sep 2026. 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-2026-89739 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-2026-89739/ (Markdown: https://insights.sbomify.com/CVE-2026-89739/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89739
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89739
- OSV: https://osv.dev/vulnerability/CVE-2026-89739

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89739/
Summaries are generated and may contain mistakes; the official description above is the record.