{"id":"CVE-2026-68429","state":"PUBLISHED","title":"drm/dp_mst: Handle torn-down topology gracefully in drm_dp_mst_topology_queue_probe()","description":"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->mst_state = false and mgr->mst_primary = NULL) concurrently\nwith a caller invoking drm_dp_mst_topology_queue_probe(). Since the check\nis already performed under mgr->lock, 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->mst_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.","publishedAt":"2026-08-12T00:07:14.640Z","updatedAt":"2026-08-17T05:05:25.387Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5f57a96e92c60f62da91d58ceb5e5acd40e7d594","status":"affected","lessThan":"b1d05cc61dfa6c4bd5e67855bec6a03e955f512d","versionType":"git"},{"version":"dbaeef363ea54f4c18112874b77503c72ba60fec","status":"affected","lessThan":"4ed6d08c4a59ee6a8cb806347f6d9873de5d229e","versionType":"git"},{"version":"dbaeef363ea54f4c18112874b77503c72ba60fec","status":"affected","lessThan":"8c6d84a54823cd839e6ce22af559925f1320c310","versionType":"git"},{"version":"dbaeef363ea54f4c18112874b77503c72ba60fec","status":"affected","lessThan":"afdff9103818656627920c21822e48a6dae2906f","versionType":"git"},{"version":"dbaeef363ea54f4c18112874b77503c72ba60fec","status":"affected","lessThan":"613059875958e7b217b250ed14c3b189f9488421","versionType":"git"},{"version":"6.6.86","status":"affected","lessThan":"6.6.148","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/display/drm_dp_mst_topology.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/display/drm_dp_mst_topology.c"]}],"references":["https://git.kernel.org/stable/c/b1d05cc61dfa6c4bd5e67855bec6a03e955f512d","https://git.kernel.org/stable/c/4ed6d08c4a59ee6a8cb806347f6d9873de5d229e","https://git.kernel.org/stable/c/8c6d84a54823cd839e6ce22af559925f1320c310","https://git.kernel.org/stable/c/afdff9103818656627920c21822e48a6dae2906f","https://git.kernel.org/stable/c/613059875958e7b217b250ed14c3b189f9488421"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:49.727Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/68xxx/CVE-2026-68429.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-68429","state":"PUBLISHED","datePublished":"2026-08-12T00:07:14.640Z","dateUpdated":"2026-08-17T05:05:25.387Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-30T09:28:09.393Z"},"containers":{"cna":{"title":"drm/dp_mst: Handle torn-down topology gracefully in drm_dp_mst_topology_queue_probe()","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->mst_state = false and mgr->mst_primary = NULL) concurrently\nwith a caller invoking drm_dp_mst_topology_queue_probe(). Since the check\nis already performed under mgr->lock, 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->mst_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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5f57a96e92c60f62da91d58ceb5e5acd40e7d594","status":"affected","lessThan":"b1d05cc61dfa6c4bd5e67855bec6a03e955f512d","versionType":"git"},{"version":"dbaeef363ea54f4c18112874b77503c72ba60fec","status":"affected","lessThan":"4ed6d08c4a59ee6a8cb806347f6d9873de5d229e","versionType":"git"},{"version":"dbaeef363ea54f4c18112874b77503c72ba60fec","status":"affected","lessThan":"8c6d84a54823cd839e6ce22af559925f1320c310","versionType":"git"},{"version":"dbaeef363ea54f4c18112874b77503c72ba60fec","status":"affected","lessThan":"afdff9103818656627920c21822e48a6dae2906f","versionType":"git"},{"version":"dbaeef363ea54f4c18112874b77503c72ba60fec","status":"affected","lessThan":"613059875958e7b217b250ed14c3b189f9488421","versionType":"git"},{"version":"6.6.86","status":"affected","lessThan":"6.6.148","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/display/drm_dp_mst_topology.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/display/drm_dp_mst_topology.c"]}],"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"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T05:05:25.387Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.86","versionEndExcluding":"6.6.148"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.12.101"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.18.42"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"7.1.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}