Bug 2535264 (CVE-2026-89893)

Summary:	CVE-2026-89893 kernel: media: cx23885: cancel NetUP CI work before 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 `cx23885` NetUP CI driver. This use-after-free vulnerability occurs when the `netup_ci_exit()` function frees a `netup_ci_state` structure while a related work item may still be pending or running. A local attacker could exploit this by triggering the module's removal, leading to a dereference of freed memory. This could result in a system crash and a denial of service.	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 11:41:35 UTC

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

media: cx23885: cancel NetUP CI work before teardown

netup_ci_exit() frees a netup_ci_state while its work item,
netup_read_ci_status(), may still be pending or running on the system
workqueue. The worker obtains the state with container_of() and
dereferences it, so it must not outlive the state.

netup_ci_init() queues the initial status read, and CI GPIO interrupts
subsequently queue the same work from netup_ci_slot_status(). During
remove, cx23885_finidev() calls free_irq() before the CI device is
unregistered. free_irq() prevents further IRQ handlers from running,
but does not drain work queued previously, so the worker can run after
netup_ci_exit() frees the state.

Call cancel_work_sync() before dvb_ca_en50221_release() and kfree().

This issue was found by an in-house static analysis tool.

Comment 1 Mauro Matteo Cascella 2026-09-22 13:27:41 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89893.mbox