Bug 2536194 (CVE-2026-90127)

Summary:	CVE-2026-90127 kernel: virtio: rtc: time out alarm requests
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 virtio-rtc driver. This vulnerability occurs because alarm requests lack a timeout. A local attacker could exploit this by triggering a surprise removal of a virtio device while an alarm request is pending. This action causes the device removal process to hang indefinitely, leading to a Denial of Service (DoS) for the affected system.	Story Points:	---
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Last Closed:		Type:	---
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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 16:43:38 UTC

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

virtio: rtc: time out alarm requests

RTC class operations run with rtc_device.ops_lock held. The virtio RTC
alarm requests currently wait without a timeout for the device to return
their requestq buffers.

On surprise removal, virtio-pci marks the virtqueues broken before
unregistering the virtio device. If an alarm request is waiting when the
device stops responding, viortc_remove() blocks in viortc_class_stop()
while trying to acquire ops_lock. The request cannot complete and device
removal hangs until the waiting task is signalled.

Use the same 60-second timeout as clock read requests for alarm reads,
alarm programming, and alarm interrupt enable requests. The existing
message reference counting keeps a timed-out request alive until a late
response or device teardown.

Comment 1 Keith Grant 2026-09-23 14:13:49 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90127.mbox