CVE-2026-98695

Received Received - Intake

USB Serial Driver Race Condition Fix

Publication date: 2026-10-18

Last updated on: 2026-10-19

Assigner: kernel.org

Description

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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-10-18

Last Modified

2026-10-19

Generated

2026-10-19

AI Q&A

2026-10-18

EPSS Evaluated

N/A

NVD

CVE-2026-98695

EUVD

EUVD-2026-103949

Affected Vendors & Products

Vendor	Product	Version / Range
Linux	Linux	f34d7a5b7010b82fe97da95496b9971435530062
Linux	Linux	f34d7a5b7010b82fe97da95496b9971435530062
Linux	Linux	f34d7a5b7010b82fe97da95496b9971435530062
Linux	Linux	f34d7a5b7010b82fe97da95496b9971435530062
Linux	Linux	2.6.26

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves a race condition between USB serial device ioctls and hangup events. The tty ioctls can call into a tty driver for a device that is already disconnected or powered down, leading to potential NULL-pointer dereferencing during break signalling. The fix serializes callbacks using the tty port mutex and adds checks to prevent accessing port data or hardware after a hangup.

Detection Guidance

This vulnerability is specific to the Linux kernel's USB serial driver and does not have network-based detection methods. Check kernel logs for USB serial driver errors or NULL pointer dereferences during device operations. Use dmesg | grep -i tty or dmesg | grep -i usb to inspect for related errors.

Impact Analysis

This vulnerability could cause system hangs or crashes if a USB serial device is disconnected during certain operations like break signalling. It may lead to kernel NULL-pointer dereferences, potentially causing denial-of-service conditions or instability in systems relying on USB serial devices.

Compliance Impact

This vulnerability does not directly affect compliance with standards like GDPR or HIPAA. It is a low-level kernel issue related to USB serial device handling that could lead to system instability or crashes but does not involve data exposure or privacy risks.

Mitigation Strategies

Update the Linux kernel to the latest stable version that includes the fix for this vulnerability. Monitor kernel updates from your distribution vendor and apply patches promptly. No additional configuration changes are required beyond the kernel update.

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