{"api_version":"1","generated_at":"2026-05-12T22:08:27+00:00","cve":"CVE-2026-43271","urls":{"html":"https://cve.report/CVE-2026-43271","api":"https://cve.report/api/cve/CVE-2026-43271.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-43271","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-43271"},"summary":{"title":"md-cluster: fix NULL pointer dereference in process_metadata_update","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmd-cluster: fix NULL pointer dereference in process_metadata_update\n\nThe function process_metadata_update() blindly dereferences the 'thread'\npointer (acquired via rcu_dereference_protected) within the wait_event()\nmacro.\n\nWhile the code comment states \"daemon thread must exist\", there is a valid\nrace condition window during the MD array startup sequence (md_run):\n\n1. bitmap_load() is called, which invokes md_cluster_ops->join().\n2. join() starts the \"cluster_recv\" thread (recv_daemon).\n3. At this point, recv_daemon is active and processing messages.\n4. However, mddev->thread (the main MD thread) is not initialized until\n   later in md_run().\n\nIf a METADATA_UPDATED message is received from a remote node during this\nspecific window, process_metadata_update() will be called while\nmddev->thread is still NULL, leading to a kernel panic.\n\nTo fix this, we must validate the 'thread' pointer. If it is NULL, we\nrelease the held lock (no_new_dev_lockres) and return early, safely\nignoring the update request as the array is not yet fully ready to\nprocess it.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-06 12:16:48","updated_at":"2026-05-08 20:00:00"},"problem_types":["CWE-476"],"metrics":[{"version":"3.1","source":"nvd@nist.gov","type":"Primary","score":"5.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}}],"references":[{"url":"https://git.kernel.org/stable/c/721599e837d3f4c0e6cc14da059612c017b6d3ec","name":"https://git.kernel.org/stable/c/721599e837d3f4c0e6cc14da059612c017b6d3ec","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f150e753cb8dd756085f46e86f2c35ce472e0a3c","name":"https://git.kernel.org/stable/c/f150e753cb8dd756085f46e86f2c35ce472e0a3c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1","name":"https://git.kernel.org/stable/c/a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/dceb5a843910004cb118148e267036104fc3ee43","name":"https://git.kernel.org/stable/c/dceb5a843910004cb118148e267036104fc3ee43","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/dec123825c1ed74d98fd5fc7571a851dea4f46ff","name":"https://git.kernel.org/stable/c/dec123825c1ed74d98fd5fc7571a851dea4f46ff","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-43271","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43271","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0ba959774e93911caff596de6391f085fb640ac4 a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0ba959774e93911caff596de6391f085fb640ac4 dec123825c1ed74d98fd5fc7571a851dea4f46ff git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0ba959774e93911caff596de6391f085fb640ac4 721599e837d3f4c0e6cc14da059612c017b6d3ec git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0ba959774e93911caff596de6391f085fb640ac4 dceb5a843910004cb118148e267036104fc3ee43 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0ba959774e93911caff596de6391f085fb640ac4 f150e753cb8dd756085f46e86f2c35ce472e0a3c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.12","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.12 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.128 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.75 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.16 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19.6 6.19.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2026","cve_id":"43271","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"linux","cpe5":"linux_kernel","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/md/md-cluster.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1","status":"affected","version":"0ba959774e93911caff596de6391f085fb640ac4","versionType":"git"},{"lessThan":"dec123825c1ed74d98fd5fc7571a851dea4f46ff","status":"affected","version":"0ba959774e93911caff596de6391f085fb640ac4","versionType":"git"},{"lessThan":"721599e837d3f4c0e6cc14da059612c017b6d3ec","status":"affected","version":"0ba959774e93911caff596de6391f085fb640ac4","versionType":"git"},{"lessThan":"dceb5a843910004cb118148e267036104fc3ee43","status":"affected","version":"0ba959774e93911caff596de6391f085fb640ac4","versionType":"git"},{"lessThan":"f150e753cb8dd756085f46e86f2c35ce472e0a3c","status":"affected","version":"0ba959774e93911caff596de6391f085fb640ac4","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/md/md-cluster.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.12"},{"lessThan":"4.12","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.128","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.75","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.16","versionType":"semver"},{"lessThanOrEqual":"6.19.*","status":"unaffected","version":"6.19.6","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.0","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.128","versionStartIncluding":"4.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.75","versionStartIncluding":"4.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.16","versionStartIncluding":"4.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.19.6","versionStartIncluding":"4.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0","versionStartIncluding":"4.12","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmd-cluster: fix NULL pointer dereference in process_metadata_update\n\nThe function process_metadata_update() blindly dereferences the 'thread'\npointer (acquired via rcu_dereference_protected) within the wait_event()\nmacro.\n\nWhile the code comment states \"daemon thread must exist\", there is a valid\nrace condition window during the MD array startup sequence (md_run):\n\n1. bitmap_load() is called, which invokes md_cluster_ops->join().\n2. join() starts the \"cluster_recv\" thread (recv_daemon).\n3. At this point, recv_daemon is active and processing messages.\n4. However, mddev->thread (the main MD thread) is not initialized until\n   later in md_run().\n\nIf a METADATA_UPDATED message is received from a remote node during this\nspecific window, process_metadata_update() will be called while\nmddev->thread is still NULL, leading to a kernel panic.\n\nTo fix this, we must validate the 'thread' pointer. If it is NULL, we\nrelease the held lock (no_new_dev_lockres) and return early, safely\nignoring the update request as the array is not yet fully ready to\nprocess it."}],"providerMetadata":{"dateUpdated":"2026-05-07T17:15:17.948Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1"},{"url":"https://git.kernel.org/stable/c/dec123825c1ed74d98fd5fc7571a851dea4f46ff"},{"url":"https://git.kernel.org/stable/c/721599e837d3f4c0e6cc14da059612c017b6d3ec"},{"url":"https://git.kernel.org/stable/c/dceb5a843910004cb118148e267036104fc3ee43"},{"url":"https://git.kernel.org/stable/c/f150e753cb8dd756085f46e86f2c35ce472e0a3c"}],"title":"md-cluster: fix NULL pointer dereference in process_metadata_update","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-43271","datePublished":"2026-05-06T11:28:55.507Z","dateReserved":"2026-05-01T14:12:55.998Z","dateUpdated":"2026-05-07T17:15:17.948Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-06 12:16:48","lastModifiedDate":"2026-05-08 20:00:00","problem_types":["CWE-476"],"metrics":{"cvssMetricV31":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":3.6}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.12","versionEndExcluding":"6.6.128","matchCriteriaId":"E90AEF03-C864-4508-AA5A-71B005F9732D"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.12.75","matchCriteriaId":"BCE16369-98ED-41CF-8995-DFDC10B288D2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.18.16","matchCriteriaId":"B4B8CDA9-BADF-4CF5-8B3B-702DE8EEA40B"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19","versionEndExcluding":"6.19.6","matchCriteriaId":"373EEEDA-FAA1-4FB4-B6ED-DB4DD99DBE67"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"43271","Ordinal":"1","Title":"md-cluster: fix NULL pointer dereference in process_metadata_upd","CVE":"CVE-2026-43271","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"43271","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nmd-cluster: fix NULL pointer dereference in process_metadata_update\n\nThe function process_metadata_update() blindly dereferences the 'thread'\npointer (acquired via rcu_dereference_protected) within the wait_event()\nmacro.\n\nWhile the code comment states \"daemon thread must exist\", there is a valid\nrace condition window during the MD array startup sequence (md_run):\n\n1. bitmap_load() is called, which invokes md_cluster_ops->join().\n2. join() starts the \"cluster_recv\" thread (recv_daemon).\n3. At this point, recv_daemon is active and processing messages.\n4. However, mddev->thread (the main MD thread) is not initialized until\n   later in md_run().\n\nIf a METADATA_UPDATED message is received from a remote node during this\nspecific window, process_metadata_update() will be called while\nmddev->thread is still NULL, leading to a kernel panic.\n\nTo fix this, we must validate the 'thread' pointer. If it is NULL, we\nrelease the held lock (no_new_dev_lockres) and return early, safely\nignoring the update request as the array is not yet fully ready to\nprocess it.","Type":"Description","Title":"md-cluster: fix NULL pointer dereference in process_metadata_upd"}]}}}