Bug 2536579 (CVE-2026-93052)

Summary:	CVE-2026-93052 kernel: misc: bcm-vk: Use acquire/release for msgq_inited
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
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 bcm-vk driver. Improper memory ordering during the initialization of message queues can cause other kernel components to read outdated queue information. This occurs when the `msgq_inited` flag is set before the message queue data is fully synchronized, leading to a state where readers perceive the queue as initialized but access stale data. This data inconsistency could potentially result in unpredictable system behavior 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 18:30:52 UTC

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

misc: bcm-vk: Use acquire/release for msgq_inited

bcm_vk_sync_msgq() fills the message queue information and then sets
msgq_inited. Readers call bcm_vk_drv_access_ok() before accessing the
message queues and their cached queue information.

atomic_set()/atomic_read() do not order those accesses. A reader can see
msgq_inited set while still seeing stale queue information. Use release
when publishing the initialized queues and acquire when checking the gate.

Keep the clear in bcm_vk_blk_drv_access() as atomic_set(). It closes the
gate and does not publish queue state to readers.

Comment 1 gkamathe 2026-09-19 20:25:26 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93052.mbox