Bug 2536491 (CVE-2026-92506)

Summary:	CVE-2026-92506 kernel: firmware: arm_scmi: Fix requested device removal race
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	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
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's ARM System Control and Management Interface (SCMI) firmware. A race condition during device removal can occur when two SCMI drivers concurrently unregister for the same protocol. This can lead to a double-free vulnerability, where memory is freed twice, potentially resulting in memory corruption or a denial of service.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-17 18:12:15 UTC

In the Linux kernel, the following vulnerability has been resolved:

firmware: arm_scmi: Fix requested device removal race

scmi_protocol_device_unrequest() drops scmi_requested_devices_mtx while
notifying listeners but continues to retain the per-protocol list head.
When two SCMI drivers for the same protocol unregister concurrently, one
thread can remove the final request and free the list head while the other
is running its notifier. The latter then dereferences the freed list head
after reacquiring the mutex and can free it a second time.

Complete the list and IDR updates, including freeing an empty list head,
before dropping the mutex. Keep the blocking notifier outside the critical
section and retain only the detached request across the callback.

Comment 1 gkamathe 2026-09-21 00:37:30 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-92506.mbox