Bug 2516228 (CVE-2026-72403)

Summary:	CVE-2026-72403 kernel: ALSA: FCP: Fix NULL pointer dereference in interface lookup
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
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 ALSA FireWire Control Protocol (FCP) component of the Linux kernel. A local attacker with a specially crafted USB device could trigger a NULL pointer dereference. This occurs because the `fcp_find_fc_interface()` function attempts to access an endpoint descriptor from a malformed USB device that does not provide any, leading to an invalid pointer dereference. This vulnerability could cause a system crash, 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 2026-08-15 06:01:34 UTC

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

ALSA: FCP: Fix NULL pointer dereference in interface lookup

A malformed USB device can provide a vendor-specific interface without
any endpoint descriptors. fcp_find_fc_interface() currently selects the
first vendor-specific interface and reads endpoint 0 from it, without
checking whether the interface actually has any endpoints.

When bNumEndpoints is zero, no endpoint array is allocated for the parsed
alternate setting, so get_endpoint(..., 0) yields an invalid endpoint
descriptor pointer. Dereferencing it through usb_endpoint_num() then
triggers a NULL pointer dereference.

Skip vendor-specific interfaces that do not have any endpoints.

Comment 1 gkamathe 2026-08-17 10:10:47 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081522-CVE-2026-72403-6666@gregkh/T