CVE-2026-98692
Received Received - Intake

Thunderbolt DP Tunnel Activation Callback Mandatory Fix

Publication date: 2026-10-18

Last updated on: 2026-10-18

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: thunderbolt: Make the DP tunnel activation callback mandatory tb_tunnel_alloc_dp() takes an optional callback which is run from dprx_work once the DPRX capabilities read has completed. Without that callback tb_dp_dprx_start() reads the capabilities synchronously and never queues the work. It however always takes a tunnel reference which is only dropped by dprx_work itself or by tb_dp_dprx_stop() when cancel_delayed_work() actually canceled that work. That reference is thus leaked for every tunnel without a callback. The only tunnels without one are those from tb_tunnel_discover_dp(), which are activated again when restoring from hibernation. Pass the callback to tb_tunnel_discover_dp() as well and drop the synchronous path such that the DPRX capabilities are always read from dprx_work. Hibernation restore then also no longer blocks for up to 12 seconds while waiting for that read to complete. Also fix up the KUnit tests.

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Meta Information

Published
2026-10-18
Last Modified
2026-10-18
Generated
2026-10-18
AI Q&A
2026-10-18
EPSS Evaluated
N/A
NVD
CVE-2026-98692
EUVD
EUVD-2026-103946

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
Linux Linux d6d458d42e1e1544a18f37f1d5c840e00d5261b9
Linux Linux d6d458d42e1e1544a18f37f1d5c840e00d5261b9
Linux Linux 6.14

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Exploitability

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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a memory leak in the Thunderbolt subsystem. The issue occurs when a callback function for DP tunnel activation is missing, causing a reference to be leaked every time a tunnel is created without the callback. This happens because the system tries to read capabilities synchronously instead of asynchronously, leading to a delayed work queue that never gets canceled properly.

Detection Guidance

This vulnerability is specific to the Linux kernel's Thunderbolt subsystem and does not have network-based detection methods. To check if your system is affected, verify the kernel version and Thunderbolt driver implementation. Use commands like 'uname -r' to check the kernel version and 'dmesg | grep thunderbolt' to inspect Thunderbolt-related logs for errors or leaks.

Impact Analysis

The impact is primarily on system stability and resource usage. The memory leak can cause gradual degradation of system performance as memory is consumed without being freed. In severe cases, this could lead to system crashes or instability, especially if multiple Thunderbolt devices are used.

Mitigation Strategies

Apply the latest kernel update provided by your Linux distribution to patch the Thunderbolt subsystem. If updating is not immediately possible, disable Thunderbolt functionality via kernel parameters (e.g., 'modprobe.blacklist=thunderbolt') or physically disconnect Thunderbolt devices until the patch is applied.

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