FKIE_CVE-2026-68429

Vulnerability from fkie_nvd - Published: 2026-08-12 00:17 - Updated: 2026-08-17 06:17
Severity
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_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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4ed6d08c4a59ee6a8cb806347f6d9873de5d229e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/613059875958e7b217b250ed14c3b189f9488421
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8c6d84a54823cd839e6ce22af559925f1320c310
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/afdff9103818656627920c21822e48a6dae2906f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b1d05cc61dfa6c4bd5e67855bec6a03e955f512d
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/display/drm_dp_mst_topology.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "b1d05cc61dfa6c4bd5e67855bec6a03e955f512d",
              "status": "affected",
              "version": "5f57a96e92c60f62da91d58ceb5e5acd40e7d594",
              "versionType": "git"
            },
            {
              "lessThan": "4ed6d08c4a59ee6a8cb806347f6d9873de5d229e",
              "status": "affected",
              "version": "dbaeef363ea54f4c18112874b77503c72ba60fec",
              "versionType": "git"
            },
            {
              "lessThan": "8c6d84a54823cd839e6ce22af559925f1320c310",
              "status": "affected",
              "version": "dbaeef363ea54f4c18112874b77503c72ba60fec",
              "versionType": "git"
            },
            {
              "lessThan": "afdff9103818656627920c21822e48a6dae2906f",
              "status": "affected",
              "version": "dbaeef363ea54f4c18112874b77503c72ba60fec",
              "versionType": "git"
            },
            {
              "lessThan": "613059875958e7b217b250ed14c3b189f9488421",
              "status": "affected",
              "version": "dbaeef363ea54f4c18112874b77503c72ba60fec",
              "versionType": "git"
            },
            {
              "lessThan": "6.6.148",
              "status": "affected",
              "version": "6.6.86",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/display/drm_dp_mst_topology.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.12"
            },
            {
              "lessThan": "6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.148",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.101",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/dp_mst: Handle torn-down topology gracefully in drm_dp_mst_topology_queue_probe()\n\nA hotplug or link-loss event can tear down the MST topology\n(setting mgr-\u003emst_state = false and mgr-\u003emst_primary = NULL) concurrently\nwith a caller invoking drm_dp_mst_topology_queue_probe(). Since the check\nis already performed under mgr-\u003elock, the condition is not a programming\nerror but a valid race -- the topology was valid when the caller decided\nto call this function, but was torn down before the lock was acquired.\n\nReplace the drm_WARN_ON() with a graceful early return. This eliminates\nspurious kernel warnings and the resulting compositor crashes observed\nwhen connecting/disconnecting DP MST monitors, while keeping the correct\nbehavior of doing nothing when MST is not active. A drm_dbg_mst() trace\nis added so the skipped probe remains observable under MST debug logging.\n\nThe existing WARN_ON(mgr-\u003emst_primary) in drm_dp_mst_topology_mgr_set_mst()\nalready catches the case where the topology is initialized twice, so no\ndiagnostic coverage is lost."
    }
  ],
  "id": "CVE-2026-68429",
  "lastModified": "2026-08-17T06:17:51.940",
  "metrics": {},
  "published": "2026-08-12T00:17:42.940",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4ed6d08c4a59ee6a8cb806347f6d9873de5d229e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/613059875958e7b217b250ed14c3b189f9488421"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8c6d84a54823cd839e6ce22af559925f1320c310"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/afdff9103818656627920c21822e48a6dae2906f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b1d05cc61dfa6c4bd5e67855bec6a03e955f512d"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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