Bug 2555161 (CVE-2026-98751)

Summary:	CVE-2026-98751 kernel: tty: abort break signalling on hangup
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 terminal (tty) subsystem. A race condition can occur when a terminal hangup interrupts an active break signaling operation, causing the kernel to communicate with a device driver after the device has already disconnected or powered down. A local attacker could exploit this vulnerability by issuing break commands during a terminal hangup to trigger 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 2026-10-18 15:57:53 UTC

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

tty: abort break signalling on hangup

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

Drivers must handle this race, but TCSBRK and TCSBRKP should still be
aborted to avoid calling back into the driver after a user-controlled
timeout (possibly even after the tty has been reopened).

Note that drivers should disable any break state on shutdown so just
return on hangup (calling break_ctl() again is racy and will most likely
fail for drivers handling the race).

Comment 1 Mauro Matteo Cascella 2026-10-23 03:18:04 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98751.mbox