Bug 2555120 (CVE-2026-98754)

Summary:	CVE-2026-98754 kernel: tty: vcc: hold port lock when clearing tty pointer in vcc_cleanup
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 Virtual Console Concentrator (VCC) driver. An omission in locking allows a race condition to occur between device cleanup operations and asynchronous event callbacks. A local attacker could exploit this timing issue to cause a use-after-free condition, potentially leading to a system crash and Denial of Service (DoS).	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 15:55:36 UTC

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

tty: vcc: hold port lock when clearing tty pointer in vcc_cleanup

vcc_cleanup() sets port->tty to NULL without holding port->lock, racing
with vcc_event() LDC callbacks that read port->tty under port->lock and
then use tty->port. This can cause a use-after-free when the callback
dereferences tty->port after cleanup has already destroyed and freed it.

Comment 1 Mauro Matteo Cascella 2026-10-23 03:39:07 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98754.mbox