Bug 2535230 (CVE-2026-89892)

Summary:	CVE-2026-89892 kernel: media: em28xx: defer audio-only extension registration
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's `em28xx` media driver. This vulnerability occurs because the audio-only path incorrectly registers extensions during device probing, leading to a duplicate device entry in an internal list. This duplicate entry can be freed while still being referenced, resulting in a use-after-free condition. A local attacker could potentially exploit this to cause a denial of service or achieve 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 11:37:55 UTC

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

media: em28xx: defer audio-only extension registration

The audio-only path registers extensions while probing the primary device.
For a dual-TS board, this happens before dev_next is created. The duplicate
device inherits is_audio_only and is then independently inserted into
em28xx_devlist.

The list is intended to contain only primary devices: extension operations
reach the secondary device through dev_next. The independently linked
secondary can be freed during disconnect while its list node remains
reachable, resulting in a use-after-free.

Defer audio-only extension registration to the module-request work item. It
runs only after probing has completed construction of the optional
secondary device, so only the primary is registered and extension callbacks
reach the secondary through dev_next.

Comment 1 Mauro Matteo Cascella 2026-09-22 12:12:22 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89892.mbox