# CVE-2026-90409: drm/panthor: Add vm_bind region with kbo range overlap check

> Missing overlap check in Panthor GPU driver allows local attackers to map kernel buffers, potentially leading to privilege escalation or code execution.

- **Severity:** Not scored
- **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:** 17 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** BELL-CVE-2026-90409, DEBIAN-CVE-2026-90409, GHSA-8w4v-ph57-xf5x, UBUNTU-CVE-2026-90409

## What is CVE-2026-90409?

CVE-2026-90409 is a missing authorization vulnerability in Linux, published on 17 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/panthor: Add vm_bind region with kbo range overlap check

When a VM is created, caller has to specify the range of the address space
carve-out set aside for mapping kernel BO's. That means vm_bind mappings of
UM-exposed BO's should not intersect with that region, but at the moment
we're not checking this.

At first, I thought of giving these values to drm_gpuvm_init() through its
reserve_{offset, range} arguments, but it turns out that is meant for VM
address spans that are not managed through the usual drm_gpuvm split/merge
circuit, so storing the end of the user VA range at VM creation time and
doing a quick check in the vm_bind ioctl path was the simplest workaround.

The new check also makes sure vm_bind range doesn't overflow the size of a
64-bit unsigned integer. That was already being done further down the call
stack inside drm_gpuvm_sm_map -> drm_gpuvm_range_valid, but it's best to
fail early in the driver before GPUVM functions are invoked so that we
won't waste time allocating vm_bind context resources.

## Which versions are affected by CVE-2026-90409?


## How do I fix CVE-2026-90409?

Apply the vendor's patch.

## Is CVE-2026-90409 being exploited?

There is no known exploitation of CVE-2026-90409 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90409 and fix it if it is affected.

What it is: CVE-2026-90409 is a missing authorization vulnerability in Linux, published on 17 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-2026-90409 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-2026-90409/ (Markdown: https://insights.sbomify.com/CVE-2026-90409/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90409
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90409
- OSV: https://osv.dev/vulnerability/CVE-2026-90409

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90409/
Summaries are generated and may contain mistakes; the official description above is the record.