Bug 2535396 (CVE-2026-90029)

Summary:	CVE-2026-90029 kernel: usb: storage: realtek_cr: fix use-after-free on disconnect
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 `realtek_cr` USB storage driver. This vulnerability, a use-after-free, occurs when the system attempts to access memory that has already been released. During a USB device disconnection, a timer within the `realtek_cr` module is deleted before its associated callback function has fully completed. This can cause the system to attempt to use freed memory, potentially leading to system instability, crashes, or 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 12:34:42 UTC

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

usb: storage: realtek_cr: fix use-after-free on disconnect

realtek_cr_destructor() calls timer_delete() before the chip containing
the timer is freed. The timer callback may still be running and can
rearm itself, resulting in a use-after-free.

Use timer_shutdown_sync() to wait for the callback and prevent further
rearming. Do this unconditionally because ss_en may be changed after
the timer is armed.

Move timer_setup() into init_realtek_cr() so the timer is initialized
before any failure path can invoke the destructor.

Found by static analysis.

Comment 1 Mauro Matteo Cascella 2026-09-17 11:00:55 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90029.mbox