CVE-2026-98695: USB: serial: fix ioctl hangup race
In the Linux kernel, the following vulnerability has been resolved:
USB: serial: fix ioctl hangup race
The tty ioctls can race with hangup and end up calling into a tty driver for a device that is already gone or powered down.
Serialise the callbacks using the tty port mutex and add the missing checks to make sure the port has not been hung up before accessing port driver data or hardware.
This specifically avoids dereferencing a NULL-pointer if a device is disconnected during lengthy break signalling.
Note that TIOCGICOUNT and TIOCMIWAIT do not access port driver data or hardware and are therefore not affected by the race.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Compensating control
Serialize tty ioctl callbacks using the tty port mutex and check that the port has not been hung up before accessing port driver data or hardware.