---
id: CVE-2026-68429
title: >-
  drm/dp_mst: Handle torn-down topology gracefully in
  drm_dp_mst_topology_queue_probe()
summary: >-
  In the Linux kernel, the following vulnerability has been resolved:


  drm/dp_mst: Handle torn-down topology gracefully in
  drm_dp_mst_topology_queue_probe()


  A hotplug or link-loss event can tear down the MST topology

  (setting mgr->mst_sta…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 5f57a96e92c60f62da91d58ceb5e5acd40e7d594 <
    b1d05cc61dfa6c4bd5e67855bec6a03e955f512d
  - >-
    Linux >= dbaeef363ea54f4c18112874b77503c72ba60fec <
    4ed6d08c4a59ee6a8cb806347f6d9873de5d229e
  - >-
    Linux >= dbaeef363ea54f4c18112874b77503c72ba60fec <
    8c6d84a54823cd839e6ce22af559925f1320c310
  - >-
    Linux >= dbaeef363ea54f4c18112874b77503c72ba60fec <
    afdff9103818656627920c21822e48a6dae2906f
  - >-
    Linux >= dbaeef363ea54f4c18112874b77503c72ba60fec <
    613059875958e7b217b250ed14c3b189f9488421
  - Linux >= 6.6.86 < 6.6.148
  - Linux 6.12
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T16:49:22.194487Z'
published: '2026-08-12'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T16:55:16.587Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-68429'
references:
  - url: 'https://git.kernel.org/stable/c/b1d05cc61dfa6c4bd5e67855bec6a03e955f512d'
  - url: 'https://git.kernel.org/stable/c/4ed6d08c4a59ee6a8cb806347f6d9873de5d229e'
  - url: 'https://git.kernel.org/stable/c/8c6d84a54823cd839e6ce22af559925f1320c310'
  - url: 'https://git.kernel.org/stable/c/afdff9103818656627920c21822e48a6dae2906f'
  - url: 'https://git.kernel.org/stable/c/613059875958e7b217b250ed14c3b189f9488421'
tags:
  - cve.org
epss: 0.00168
epssPercentile: 0.06219
ingestedAt: '2026-11-06T18:00:12.608Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

drm/dp_mst: Handle torn-down topology gracefully in drm_dp_mst_topology_queue_probe()

A hotplug or link-loss event can tear down the MST topology
(setting mgr->mst_state = false and mgr->mst_primary = NULL) concurrently
with a caller invoking drm_dp_mst_topology_queue_probe(). Since the check
is already performed under mgr->lock, the condition is not a programming
error but a valid race -- the topology was valid when the caller decided
to call this function, but was torn down before the lock was acquired.

Replace the drm_WARN_ON() with a graceful early return. This eliminates
spurious kernel warnings and the resulting compositor crashes observed
when connecting/disconnecting DP MST monitors, while keeping the correct
behavior of doing nothing when MST is not active. A drm_dbg_mst() trace
is added so the skipped probe remains observable under MST debug logging.

The existing WARN_ON(mgr->mst_primary) in drm_dp_mst_topology_mgr_set_mst()
already catches the case where the topology is initialized twice, so no
diagnostic coverage is lost.

## Affected

- `Linux >= 5f57a96e92c60f62da91d58ceb5e5acd40e7d594 < b1d05cc61dfa6c4bd5e67855bec6a03e955f512d`
- `Linux >= dbaeef363ea54f4c18112874b77503c72ba60fec < 4ed6d08c4a59ee6a8cb806347f6d9873de5d229e`
- `Linux >= dbaeef363ea54f4c18112874b77503c72ba60fec < 8c6d84a54823cd839e6ce22af559925f1320c310`
- `Linux >= dbaeef363ea54f4c18112874b77503c72ba60fec < afdff9103818656627920c21822e48a6dae2906f`
- `Linux >= dbaeef363ea54f4c18112874b77503c72ba60fec < 613059875958e7b217b250ed14c3b189f9488421`
- `Linux >= 6.6.86 < 6.6.148`
- `Linux 6.12`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.