Bug 2532239 (CVE-2026-89737)

Summary:	CVE-2026-89737 kernel: usb: typec: thunderbolt: Disable work before freeing tbt on remove
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 Type-C Thunderbolt driver. The `tbt_altmode_remove()` function fails to properly disable and drain work items before freeing associated plug and cable references. This oversight can lead to a use-after-free vulnerability, where the system attempts to access memory that has already been released. A local attacker could potentially exploit this to cause a system crash, leading to a denial of service, or possibly 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 2026-09-11 21:37:24 UTC

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

usb: typec: thunderbolt: Disable work before freeing tbt on remove

tbt_altmode_remove() drops the plug and cable references without
draining tbt->work. The work function dereferences those references,
and can also requeue itself in its error path. The VDM callbacks can
queue the same work item.

Disable and drain tbt->work before dropping the references. This waits
for an existing invocation and prevents subsequent schedule_work()
calls from queueing it during teardown.

This issue was found by an in-house static analysis tool and confirmed
by manual code review.

Comment 1 Keith Grant 2026-09-21 16:08:05 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89737.mbox