# CVE-2023-54299: usb: typec: bus: verify partner exists in typec_altmode_attention

> A local attacker with physical access can cause a kernel crash via a null pointer dereference in the USB Type-C subsystem during specific data role swaps.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 30 Dec 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-54299, DEBIAN-CVE-2023-54299, GHSA-4784-9v76-jqjx, UBUNTU-CVE-2023-54299

## What is CVE-2023-54299?

CVE-2023-54299 is a vulnerability in Linux, published on 30 Dec 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

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

usb: typec: bus: verify partner exists in typec_altmode_attention

Some usb hubs will negotiate DisplayPort Alt mode with the device
but will then negotiate a data role swap after entering the alt
mode. The data role swap causes the device to unregister all alt
modes, however the usb hub will still send Attention messages
even after failing to reregister the Alt Mode. type_altmode_attention
currently does not verify whether or not a device's altmode partner
exists, which results in a NULL pointer error when dereferencing
the typec_altmode and typec_altmode_ops belonging to the altmode
partner.

Verify the presence of a device's altmode partner before sending
the Attention message to the Alt Mode driver.

## Which versions are affected by CVE-2023-54299?


## How do I fix CVE-2023-54299?

Apply the vendor's patch.

## Is CVE-2023-54299 being exploited?

There is no known exploitation of CVE-2023-54299 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-54299 and fix it if it is affected.

What it is: CVE-2023-54299 is a vulnerability in Linux, published on 30 Dec 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2023-54299 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-2023-54299/ (Markdown: https://insights.sbomify.com/CVE-2023-54299/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-54299
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-54299
- OSV: https://osv.dev/vulnerability/CVE-2023-54299

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-54299/
Summaries are generated and may contain mistakes; the official description above is the record.