# CVE-2026-90430: iommu/tegra241-cmdqv: Publish an LVCMDQ only after it is fully initialized

> A race condition in the Tegra241 IOMMU driver allows a local attacker to trigger a kernel crash via null pointer dereference during device initialization.

- **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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-90430, DEBIAN-CVE-2026-90430, GHSA-fq43-87xx-qq28, UBUNTU-CVE-2026-90430

## What is CVE-2026-90430?

CVE-2026-90430 is a 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:

iommu/tegra241-cmdqv: Publish an LVCMDQ only after it is fully initialized

tegra241_vintf_init_lvcmdq() stores the freshly allocated vcmdq pointer to
the vintf->lvcmdqs[] array, before tegra241_vcmdq_alloc_smmu_cmdq() builds
the vcmdq->cmdq. The error ISR dereferences that cmdq, so a latched LVCMDQ
error (e.g. one inherited across a kexec) firing in this window would make
tegra241_vintf0_handle_error() pass the still-zeroed arm_smmu_cmdq down to
__arm_smmu_cmdq_skip_err(), dereferencing NULL queue register pointers.

Drop the store from tegra241_vintf_init_lvcmdq() and publish the vcmdq at
the end of the allocation instead, with an smp_store_release() that pairs
with an smp_load_acquire() in the ISR, which can see a fully built LVCMDQ
or NULL.

The user-owned LVCMDQ allocation moves accordingly, publishing the vcmdq
once tegra241_vcmdq_hw_init_user() succeeds, using a plain store since a
user VINTF's lvcmdqs[] has no lockless reader -- the error ISR only walks
the VINTF0 array.

## Which versions are affected by CVE-2026-90430?


## How do I fix CVE-2026-90430?

Apply the vendor's patch.

## Is CVE-2026-90430 being exploited?

There is no known exploitation of CVE-2026-90430 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90430 and fix it if it is affected.

What it is: CVE-2026-90430 is a 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-2026-90430 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-2026-90430/ (Markdown: https://insights.sbomify.com/CVE-2026-90430/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90430
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90430
- OSV: https://osv.dev/vulnerability/CVE-2026-90430

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90430/
Summaries are generated and may contain mistakes; the official description above is the record.