Bug 2536178 (CVE-2026-90335)

Summary:	CVE-2026-90335 kernel: tty: skip cdev_del() when no cdev is registered
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
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 handling of TTY devices. When a TTY device registration fails before a character device (cdev) is allocated, the serial core retains the port. Subsequent removal of this port can lead to a null-pointer dereference if cdev_del() is called with a NULL cdev slot. This issue could allow a local attacker to cause a system crash, resulting in a 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 2026-09-17 16:41:35 UTC

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

tty: skip cdev_del() when no cdev is registered

TTY device registration can fail before a cdev is allocated.
Serial core keeps the port so setserial can still use it, and later
removal passes the NULL cdev slot to cdev_del(), causing a NULL-pointer
dereference.

Only delete the cdev when the slot is not NULL.

Comment 1 gkamathe 2026-09-21 20:01:05 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90335.mbox