Bug 2555149 (CVE-2026-98772)

Summary:	CVE-2026-98772 kernel: USB: serial: fix port tear down use-after-free
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 serial subsystem. This flaw may result in a Denial of Service (DoS) due to a use-after-free vulnerability. During multiport device disconnection, a race condition allows background completion handlers to access port driver data after it has already been freed. A local user or an attacker with physical access could exploit this timing issue during device teardown to trigger a system crash.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
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Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-10-18 15:57:11 UTC

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

USB: serial: fix port tear down use-after-free

Some drivers for multiport devices access port driver data from
completion handlers of shared URBs submitted at attach() or first open()
and stopped at disconnect() or last close(), respectively.

A simple NULL check before accessing the driver data makes sure that a
port state container has at least been allocated, but a completion
handler can still race with port tear down.

Reorder the disconnect handling so that ports are not deregistered (and
their driver data freed) until after all ports have been hung up and the
driver disconnect() callback has run so that all I/O has been stopped.

Comment 1 Mauro Matteo Cascella 2026-10-23 06:36:08 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98772.mbox