Bug 2546343 (CVE-2026-98316)

Summary:	CVE-2026-98316 kernel: kernel: Denial of Service via race condition in ALSA bcd2000 driver
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:	rhel-process-autobot, 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 ALSA bcd2000 driver. This vulnerability allows a local user to cause a Denial of Service (DoS) by crashing the system. A race condition exists between ongoing MIDI data processing and USB device disconnection, allowing active tasks to access memory after it has been freed. By disconnecting the device during active data transfer, a user can trigger this use-after-free flaw to crash the operating system.	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 2026-10-06 09:01:30 UTC

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

ALSA: bcd2000: Fix race between rawmidi and disconnect

Although we tried to fix the potential UAF issues at USB disconnect on
bcd2000 driver, there is still an overlooked case -- namely, when a
rawmidi trigger callback has been already running at USB disconnect
handling, the in-flight function (e.g. bcd2000_midi_send()) could
still access the URB, because the previous URB NULL-check & clearance
was considered only for the URB complete callbacks, but not about the
parallel rawmidi operations.

For addressing the race, this patch introduced a new spinlock that
covers each rawmidi operation as well as the rawmidi handling in the
complete callback.  The URB is cleared with the lock, so it guarantees
that the pending rawmidi task already finished or a NULL check is
effective.