# CVE-2026-99151: drm/amd/display: Fix NULL sink dereference in USB4 bandwidth functions


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 28 Oct 2026
- **Updated:** 28 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-99151, GHSA-ff22-8xjr-7629, UBUNTU-CVE-2026-99151

## What is CVE-2026-99151?

CVE-2026-99151 is a vulnerability in Linux, published on 28 Oct 2026. 

### Official description

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

drm/amd/display: Fix NULL sink dereference in USB4 bandwidth functions

allocate_usb4_bandwidth_for_stream() and allocate_usb4_bandwidth() both
use ASSERT(stream->sink) before dereferencing stream->sink->link. ASSERT
is compiled out in production builds, so a NULL stream->sink causes a
NULL pointer dereference.

link_set_dpms_off() already guards two earlier accesses to stream->sink
with explicit NULL checks, confirming that stream->sink can legitimately
be NULL. The subsequent call to deallocate_usb4_bandwidth() had no
equivalent guard.

Replace the ASSERT() calls with proper NULL checks that return false
early, and add a matching stream->sink guard at the call site in
link_set_dpms_off() consistent with the surrounding pattern.

v2: Keep the existing ASSERT() calls for diagnostics (to report
    unexpected NULL sink), and add explicit NULL checks that return false
    before dereferencing stream->sink. Also add a matching stream->sink
    guard at the deallocation call site in link_set_dpms_off(). (Alex)

(cherry picked from commit 98029a0ce61feb52c563f65349dd9b25f672e355)

## Which versions are affected by CVE-2026-99151?


## How do I fix CVE-2026-99151?

Upgrade to a fixed version.

## Is CVE-2026-99151 being exploited?

There is no known exploitation of CVE-2026-99151 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-99151 and fix it if it is affected.

What it is: CVE-2026-99151 is a vulnerability in Linux, published on 28 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-99151 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-2026-99151/ (Markdown: https://insights.sbomify.com/CVE-2026-99151/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-99151
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-99151
- OSV: https://osv.dev/vulnerability/CVE-2026-99151

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-99151/
Summaries are generated and may contain mistakes; the official description above is the record.