Bug 2541202 (CVE-2026-98086)

Summary:	CVE-2026-98086 kernel: ALSA: ump: do not touch legacy_rmidi before it exists
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 Advanced Linux Sound Architecture (ALSA) subsystem. When configuring Universal MIDI Packet (UMP) devices, the driver prematurely treats endpoint structures as fully initialized before legacy MIDI data structures are attached. A local user or connected device sending packets during this window can trigger a null pointer dereference, causing a kernel crash and resulting in a Denial of Service (DoS).	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 2026-09-25 11:00:13 UTC

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

ALSA: ump: do not touch legacy_rmidi before it exists

snd_ump_parse_endpoint() sets ump->parsed on every exit, including
error, before the caller attaches the legacy rawmidi device.
ump_handle_ep_name_msg() then treats parsed as "legacy_rmidi is live"
and calls ump_legacy_set_rawmidi_name(), which snprintf()s into
ump->legacy_rmidi->name. If a UMP packet arrives in that window
(IRQ path from snd_ump_receive), legacy_rmidi is still NULL
(KASAN null-ptr-deref in snprintf).

Guard the legacy helpers. parsed only means endpoint info was
parsed, not that legacy_rmidi exists.

Comment 1 Keith Grant 2026-09-25 17:50:34 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98086.mbox