{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "0ba959774e93911caff596de6391f085fb640ac4"
            },
            {
              "fixed": "a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1"
            },
            {
              "fixed": "dec123825c1ed74d98fd5fc7571a851dea4f46ff"
            },
            {
              "fixed": "721599e837d3f4c0e6cc14da059612c017b6d3ec"
            },
            {
              "fixed": "dceb5a843910004cb118148e267036104fc3ee43"
            },
            {
              "fixed": "f150e753cb8dd756085f46e86f2c35ce472e0a3c"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.12.0"
            },
            {
              "fixed": "6.6.128"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.75"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.16"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "6.19.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43271.json"
  },
  "details": "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-\u003ejoin().\n2. join() starts the \"cluster_recv\" thread (recv_daemon).\n3. At this point, recv_daemon is active and processing messages.\n4. However, mddev-\u003ethread (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-\u003ethread 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.",
  "id": "CVE-2026-43271",
  "modified": "2026-07-08T05:38:05.840368411Z",
  "published": "2026-05-06T11:28:55.507Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/721599e837d3f4c0e6cc14da059612c017b6d3ec"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dceb5a843910004cb118148e267036104fc3ee43"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dec123825c1ed74d98fd5fc7571a851dea4f46ff"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f150e753cb8dd756085f46e86f2c35ce472e0a3c"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43271.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43271"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.7.5",
  "summary": "md-cluster: fix NULL pointer dereference in process_metadata_update"
}