Bug 2535383 (CVE-2026-90022)

Summary:	CVE-2026-90022 kernel: usb: gadget: f_midi2: fix use-after-free in string attribute show path
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
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, specifically within the `usb: gadget: f_midi2` component. A race condition occurs when handling string attributes, where a pointer to freed memory can be accessed. This use-after-free vulnerability could lead to system instability, information disclosure, or potentially arbitrary code execution.	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 2026-09-16 12:28:28 UTC

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

usb: gadget: f_midi2: fix use-after-free in string attribute show path

f_midi2_opts_str_show() takes the string lock internally, but its
callers dereference the opts->info.<field> pointer before calling it,
outside the lock. This races with f_midi2_opts_str_store(), which
frees the old string under opts->lock when the attribute is written
concurrently, the show path can read a pointer that gets freed
before the lock inside str_show() is even taken.

Change f_midi2_opts_str_show() to take a pointer to the string field,
matching the existing pattern in f_midi2_opts_str_store(), and
dereference it only after the lock is held. Update all three callers
(iface_name, block name, and the EP string option macro) accordingly.

Comment 1 Mauro Matteo Cascella 2026-09-17 15:15:58 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90022.mbox