# CVE-2026-23009: xhci: sideband: don't dereference freed ring when removing sideband endpoint

> A null pointer dereference in the Linux kernel xHCI sideband driver can cause a system crash during device removal or resume operations.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 25 Jan 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2026-23009, DEBIAN-CVE-2026-23009, GHSA-h2fj-cf53-2c8q, UBUNTU-CVE-2026-23009

## What is CVE-2026-23009?

CVE-2026-23009 is a medium-severity vulnerability in Linux kernel, published on 25 Jan 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:

xhci: sideband: don't dereference freed ring when removing sideband endpoint

xhci_sideband_remove_endpoint() incorrecly assumes that the endpoint is
running and has a valid transfer ring.

Lianqin reported a crash during suspend/wake-up stress testing, and
found the cause to be dereferencing a non-existing transfer ring
'ep->ring' during xhci_sideband_remove_endpoint().

The endpoint and its ring may be in unknown state if this function
is called after xHCI was reinitialized in resume (lost power), or if
device is being re-enumerated, disconnected or endpoint already dropped.

Fix this by both removing unnecessary ring access, and by checking
ep->ring exists before dereferencing it. Also make sure endpoint is
running before attempting to stop it.

Remove the xhci_initialize_ring_info() call during sideband endpoint
removal as is it only initializes ring structure enqueue, dequeue and
cycle state values to their starting values without changing actual
hardware enqueue, dequeue and cycle state. Leaving them out of sync
is worse than leaving it as it is. The endpoint will get freed in after
this in most usecases.

If the (audio) class driver want's to reuse the endpoint after offload
then it is up to the class driver to ensure endpoint is properly set up.

## Which versions are affected by CVE-2026-23009?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23009?

Apply the vendor's patch.

## Is CVE-2026-23009 being exploited?

There is no known exploitation of CVE-2026-23009 in the wild and no public exploit code.

Public exploit code:

- https://github.com/George0Papasotiriou/CVE-2026-23009-DICOM-Network-Image-Injection-Without-Authentication (github_poc): https://github.com/George0Papasotiriou/CVE-2026-23009-DICOM-Network-Image-Injection-Without-Authentication

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23009 and fix it if it is affected.

What it is: CVE-2026-23009 is a medium-severity vulnerability in Linux kernel, published on 25 Jan 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-2026-23009 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-23009/ (Markdown: https://insights.sbomify.com/CVE-2026-23009/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23009
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23009
- OSV: https://osv.dev/vulnerability/CVE-2026-23009

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23009/
Summaries are generated and may contain mistakes; the official description above is the record.