# CVE-2026-90035: drm/amd/display: fix division by zero in get_estimated_bw()

> A malicious USB4/DPIA device can trigger a division by zero in the Linux kernel, causing a denial of service.

- **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:** 16 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-101187, BELL-CVE-2026-90035, DEBIAN-CVE-2026-90035, GHSA-535w-j2qq-gp7f, UBUNTU-CVE-2026-90035

## What is CVE-2026-90035?

CVE-2026-90035 is a denial of service vulnerability in Linux, published on 16 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:

drm/amd/display: fix division by zero in get_estimated_bw()

get_estimated_bw() divides by link->dpia_bw_alloc_config.bw_granularity,
which is zeroed by reset_bw_alloc_struct() and only populated once
DP_TUNNELING_BW_ALLOC_CAP_CHANGED has been handled.

link_dp_dpia_handle_bw_alloc_status(), the DPCD interrupt handler,
calls get_estimated_bw() whenever DP_TUNNELING_ESTIMATED_BW_CHANGED
is set, independently of whether DP_TUNNELING_BW_ALLOC_CAP_CHANGED
has ever fired for that link. A connected USB4/DPIA tunneling device
that reports an estimated-bandwidth change before ever reporting a
capability change drives a division by zero in this IRQ path.

link_dpia_send_bw_alloc_request() already guards the same
bw_granularity division; add the identical guard here rather than
introducing a new pattern.

(cherry picked from commit f2a961457c33dc34223aad5c9e8971de34a4eed3)

## Which versions are affected by CVE-2026-90035?


## How do I fix CVE-2026-90035?

Apply the vendor's patch.

## Is CVE-2026-90035 being exploited?

There is no known exploitation of CVE-2026-90035 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90035 and fix it if it is affected.

What it is: CVE-2026-90035 is a denial of service vulnerability in Linux, published on 16 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-2026-90035 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-2026-90035/ (Markdown: https://insights.sbomify.com/CVE-2026-90035/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90035
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90035
- OSV: https://osv.dev/vulnerability/CVE-2026-90035

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90035/
Summaries are generated and may contain mistakes; the official description above is the record.