Bug 2536435 (CVE-2026-90397)

Summary: CVE-2026-90397 kernel: firmware: qcom: scm: Fix NULL dereference in IRQ handler before __scm is published
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Linux kernel's Qualcomm (qcom) Secure Channel Manager (SCM) firmware component. This vulnerability allows for a NULL pointer dereference due to improper initialization of a shared memory pointer. An attacker could exploit this timing issue, potentially leading to a system crash and a Denial of Service (DoS) for the affected system.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-17 17:50:28 UTC 
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.
Comment 1 gkamathe 2026-09-21 09:34:23 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90397.mbox