# CVE-2026-74575: thunderbolt: Prevent XDomain delayed work use-after-free on disconnect

> A race condition in the Linux kernel Thunderbolt driver allows a use-after-free during device disconnect, potentially leading to code execution or system crash.

- **Severity:** High 8.8 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 15 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-74575, DEBIAN-CVE-2026-74575, GHSA-87c7-v43r-f3f4, UBUNTU-CVE-2026-74575

## What is CVE-2026-74575?

CVE-2026-74575 is a high-severity use after free vulnerability in Linux, published on 15 Aug 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:

thunderbolt: Prevent XDomain delayed work use-after-free on disconnect

tb_xdp_handle_request() runs on system_wq and queues
xd->state_work via queue_delayed_work() in three request handlers:
PROPERTIES_CHANGED_REQUEST, UUID_REQUEST (via start_handshake),
and LINK_STATE_CHANGE_REQUEST.  Similarly, update_xdomain() queues
xd->properties_changed_work when local properties change.

Concurrently, tb_xdomain_remove() calls stop_handshake() which does
cancel_delayed_work_sync() on both delayed works.  Later,
tb_xdomain_unregister() calls device_unregister() which eventually
frees the xdomain.  Since commit 559c1e1e0134 ("thunderbolt: Run
tb_xdp_handle_request() in system workqueue") moved the request
handler off tb->wq, the handler and the remove path are no longer
serialized.  If queue_delayed_work() executes after
cancel_delayed_work_sync() but before the xdomain is freed, the
delayed work fires on a freed object.

Add xd->removing that tb_xdomain_remove() sets under xd->lock
before calling stop_handshake().  Each external queue site holds
the same lock and checks removing before calling
queue_delayed_work().  This provides the mutual exclusion needed:
either the queue site acquires the lock first and queues work that
the subsequent cancel will see, or the remove path acquires the
lock first and the queue site observes removing == true and skips
the queue.

## Which versions are affected by CVE-2026-74575?


## How do I fix CVE-2026-74575?

Apply the vendor's patch.

## Is CVE-2026-74575 being exploited?

There is no known exploitation of CVE-2026-74575 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74575 and fix it if it is affected.

What it is: CVE-2026-74575 is a high-severity use after free vulnerability in Linux, published on 15 Aug 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-2026-74575 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-2026-74575/ (Markdown: https://insights.sbomify.com/CVE-2026-74575/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74575
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74575
- OSV: https://osv.dev/vulnerability/CVE-2026-74575

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74575/
Summaries are generated and may contain mistakes; the official description above is the record.