# CVE-2026-90397: firmware: qcom: scm: Fix NULL dereference in IRQ handler before __scm is published

> A race condition in the Qualcomm SCM driver causes a NULL pointer dereference during probe, leading to a kernel crash and 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:** 17 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-101921, BELL-CVE-2026-90397, DEBIAN-CVE-2026-90397, GHSA-gcqw-f4ff-hx84, UBUNTU-CVE-2026-90397

## What is CVE-2026-90397?

CVE-2026-90397 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:

firmware: qcom: scm: Fix NULL dereference in IRQ handler before __scm is published

In qcom_scm_probe(), devm_request_threaded_irq() is called before
smp_store_release(&__scm, scm). Two paths can dereference __scm before
it is published, both causing a NULL pointer dereference.

The IRQ handler receives scm via its data argument but passes only wq_ctx
to qcom_scm_waitq_wakeup() and qcom_scm_get_completion(), which then
dereference __scm directly. Thread scm through both functions so the IRQ
handler path never touches __scm.

Non-atomic SMC calls made during probe (e.g. from qcom_tzmem_init via
qcom_scm_shm_bridge_enable) can return WAITQ_SLEEP, causing
qcom_scm_wait_for_wq_completion() to run before __scm is published and
dereference it. Add platform_set_drvdata(pdev, scm) early in probe and
change qcom_scm_wait_for_wq_completion() to take the device pointer and
use dev_get_drvdata() to reach scm, removing any dependency on __scm.

## Which versions are affected by CVE-2026-90397?


## How do I fix CVE-2026-90397?

Apply the vendor's patch.

## Is CVE-2026-90397 being exploited?

There is no known exploitation of CVE-2026-90397 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90397 and fix it if it is affected.

What it is: CVE-2026-90397 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-2026-90397 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-2026-90397/ (Markdown: https://insights.sbomify.com/CVE-2026-90397/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90397
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90397
- OSV: https://osv.dev/vulnerability/CVE-2026-90397

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90397/
Summaries are generated and may contain mistakes; the official description above is the record.