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.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
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.
Sources
Also known as AZL-101921, BELL-CVE-2026-90397, DEBIAN-CVE-2026-90397, GHSA-gcqw-f4ff-hx84, UBUNTU-CVE-2026-90397.