Bug 2555074 (CVE-2026-98695)

Summary:	CVE-2026-98695 kernel: USB: serial: fix ioctl hangup race
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. A local user could cause a Denial of Service (DoS) due to a race condition between input/output control (ioctl) operations and device disconnection. If a USB serial device is disconnected during an active operation, the driver may attempt to access released resources, triggering a null-pointer dereference and a system crash.	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 2026-10-18 15:52:57 UTC

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

USB: serial: fix ioctl hangup race

The tty ioctls can race with hangup and end up calling into a tty driver
for a device that is already gone or powered down.

Serialise the callbacks using the tty port mutex and add the missing
checks to make sure the port has not been hung up before accessing port
driver data or hardware.

This specifically avoids dereferencing a NULL-pointer if a device is
disconnected during lengthy break signalling.

Note that TIOCGICOUNT and TIOCMIWAIT do not access port driver data or
hardware and are therefore not affected by the race.

Comment 1 Mauro Matteo Cascella 2026-10-22 04:22:41 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98695.mbox