CVE-2026-98751: tty: abort break signalling on hangup

CVE-2026-98751: tty: abort break signalling on hangup

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

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).

The Linux kernel CVE team has assigned CVE-2026-98751 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 2.6.26 with commit f34d7a5b7010b82fe97da95496b9971435530062 and fixed in 6.12.113 with commit 3bc82999fb85cecc7eb6ec1755ee7d698aa1e783
	Issue introduced in 2.6.26 with commit f34d7a5b7010b82fe97da95496b9971435530062 and fixed in 6.18.56 with commit 94af6cd832e9b4ce39a8fb59144a8f09ab56fd35
	Issue introduced in 2.6.26 with commit f34d7a5b7010b82fe97da95496b9971435530062 and fixed in 7.2.10 with commit c8ccd3b2013daaf77b98f8a6724fcf4d2c5c52d6
	Issue introduced in 2.6.26 with commit f34d7a5b7010b82fe97da95496b9971435530062 and fixed in 7.3-rc6 with commit 845a2737e0f5ffe5ca8d38de556012b0c9472cdd

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-98751
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/tty/tty_io.c
	include/linux/tty.h


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/3bc82999fb85cecc7eb6ec1755ee7d698aa1e783
	https://git.kernel.org/stable/c/94af6cd832e9b4ce39a8fb59144a8f09ab56fd35
	https://git.kernel.org/stable/c/c8ccd3b2013daaf77b98f8a6724fcf4d2c5c52d6
	https://git.kernel.org/stable/c/845a2737e0f5ffe5ca8d38de556012b0c9472cdd