Bug 2536752 (CVE-2026-90334)

Summary:	CVE-2026-90334 kernel: tty: clear cdev pointer after cdev_add() failure
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
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 tty subsystem. When a character device (cdev) is added and fails, a pointer to the device's memory is not properly cleared. This 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 (denial of service) or, in some scenarios, execute arbitrary code.	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 2026-09-17 19:25:28 UTC

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

tty: clear cdev pointer after cdev_add() failure

tty_cdev_add() drops the cdev reference when cdev_add() fails, but
leaves driver->cdevs[index] pointing to freed memory.
tty_unregister_device() later passes that stale pointer to cdev_del(),
causing a use-after-free.

Clear the slot after dropping the reference.

Comment 1 gkamathe 2026-09-21 19:46:23 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90334.mbox