Bug 2516510 (CVE-2026-72446)

Summary:	CVE-2026-72446 kernel: ALSA: usb-audio: qcom: reject stream disable with no active interface
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
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 USB audio subsystem (qcom). An unprivileged local user can exploit this vulnerability by sending a crafted request over AF_QIPCRTR to disable a stream with no active interface. This can lead to an out-of-bounds write, resulting in memory corruption or a kernel oops. Successful exploitation could allow an attacker to cause a denial of service or potentially escalate privileges.	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 2026-08-15 06:16:17 UTC

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

ALSA: usb-audio: qcom: reject stream disable with no active interface

handle_uaudio_stream_req() resolves an interface index with
info_idx_from_ifnum(), which returns -EINVAL when no interface matches.
The enable branch and the response: cleanup label both guard against a
negative index, but the disable branch does not: it forms
info = &uadev[pcm_card_num].info[info_idx] and dereferences it.

uadev[].info is a pointer allocated only when a stream is first enabled,
so a negative info_idx on the disable path is unsafe in two ways:

 - If the card was never enabled, .info is NULL and &info[-EINVAL] is a
   wild pointer; reading info->data_ep_pipe faults (kernel oops).

 - If the card was enabled at least once (.info allocated) and the
   disable names an interface that does not match, &info[-EINVAL] points
   before the allocation; info->data_ep_pipe / info->sync_ep_pipe are an
   out-of-bounds slab read and, when non-zero, an out-of-bounds 4-byte
   write (both pipe fields are cleared to 0). That is memory corruption,
   not just a NULL dereference.

The request is reachable from unprivileged local userspace over
AF_QIPCRTR. Reject a disable request with no resolved interface, matching
the guard the enable path already has.

Comment 1 Keith Grant 2026-08-19 16:50:55 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081530-CVE-2026-72446-b0bb@gregkh/T