# CVE-2026-90427: iommu/tegra241-cmdqv: Don't fall back to a freed smmu after devm_krealloc()

> A use-after-free vulnerability in the Linux kernel's Tegra241 CMDQV driver allows attackers to cause denial of service or execute arbitrary code.

- **Severity:** High 7.4 (`CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 21 Oct 2026
- **Also known as:** BELL-CVE-2026-90427, DEBIAN-CVE-2026-90427, GHSA-7wgr-jrpm-fgrv, UBUNTU-CVE-2026-90427

## What is CVE-2026-90427?

CVE-2026-90427 is a high-severity use after free 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: Don't fall back to a freed smmu after devm_krealloc()

__tegra241_cmdqv_probe() uses devm_krealloc() to grow @smmu into the larger
tegra241_cmdqv, which frees the original @smmu once it relocates. A failure
after that returned NULL, and the caller then dereferenced the freed @smmu
on its fallback path.

Return an int and take @smmu by reference instead, then update *smmu to the
reallocated pointer after devm_krealloc() succeeds, so the caller and its
fallback path both use the live @smmu rather than the freed original.

## Which versions are affected by CVE-2026-90427?


## How do I fix CVE-2026-90427?

Apply the vendor's patch.

## Is CVE-2026-90427 being exploited?

There is no known exploitation of CVE-2026-90427 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90427 and fix it if it is affected.

What it is: CVE-2026-90427 is a high-severity use after free 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-2026-90427 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-2026-90427/ (Markdown: https://insights.sbomify.com/CVE-2026-90427/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90427
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90427
- OSV: https://osv.dev/vulnerability/CVE-2026-90427

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90427/
Summaries are generated and may contain mistakes; the official description above is the record.