Bug 2532401 (CVE-2026-89735)

Summary:	CVE-2026-89735 kernel: usb: gadget: midi2: remove default configfs groups on teardown
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 USB gadget MIDI2 driver. The driver fails to properly remove default configuration file system (configfs) groups during teardown, leading to a resource leak. A local attacker could exploit this vulnerability to cause memory exhaustion, potentially resulting in a denial of service (DoS) on the affected system.	Story Points:	---
Clone Of:		Environment:
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 2026-09-11 22:47:53 UTC

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

usb: gadget: midi2: remove default configfs groups on teardown

f_midi2_alloc_inst() creates default configfs child groups for the
default endpoint and default block using configfs_add_default_group(),
setting their internal refcount to 1.

However, during function teardown in f_midi2_free_inst() or EP cleanup
in f_midi2_ep_opts_release(), configfs_remove_default_groups() is
never called, therefore never dropping the refcount and leaking struct
f_midi2_ep_opts and f_midi2_block_opts.

Add the missing configfs_remove_default_groups() in the afformentioned
functions to free the structs properly.

Comment 1 Keith Grant 2026-09-21 15:55:09 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89735.mbox