---
id: "CVE-2026-98692"
kind: "vulnerability"
aliases: ["CVE-2026-98692"]
title: "Linux kernel Thunderbolt: DP tunnel reference leak on hibernation restore"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["laptops", "linux-kernel", "other", "thunderbolt", "workstations"]
not_affected_if: ["driver-not-loaded", "no-thunderbolt-hardware"]
published_at: "2026-10-18T16:17:22+00:00"
first_seen_at: "2026-10-23T21:57:16+00:00"
updated_at: "2026-10-25T05:19:03+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98692", "first_seen_at": "2026-10-23T21:57:16+00:00"}]
---

# Linux kernel Thunderbolt: DP tunnel reference leak on hibernation restore

In the Linux kernel's Thunderbolt driver, DisplayPort tunnels created without an activation callback leak a tunnel reference on every activation. The sources do not describe an attacker-facing effect beyond resource exhaustion and slower hibernation restore.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run `uname -r` and compare against the fixed kernel release listed in the NVD entry for CVE-2026-98692.
- Check whether Thunderbolt or USB4 hardware with DisplayPort tunnelling is present, for example with `boltctl list`.

## Fix

- Update the Linux kernel to a release that includes the upstream commit resolving CVE-2026-98692 (version unknown from the sources).

## Timeline

- 2026-10-23T21:57:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98692

## From the sources

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.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_