{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "6714d8e86bf443f6f7af50f9d432025649f091f5"
            },
            {
              "fixed": "f8658ee3327f73bd81c0bcd07cdeb5a8527fac98"
            },
            {
              "fixed": "de10cd3b062a5235af754925fcf49beb5a1109d4"
            },
            {
              "fixed": "2487bea2098322669f0563baff53e797486b823f"
            },
            {
              "fixed": "ea5b5609305a8437bc955a0834a530c12246d78f"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.16"
            },
            {
              "fixed": "6.12.109"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.50"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89495.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: bound namelen in dlm_migrate_request_handler\n\nPatch series \"ocfs2/dlm: bound peer-controlled lengths in the o2dlm\".\n\nThe o2dlm receive handlers trust u8 length and count fields from the wire\nwithout bounding them, so a node in a DLM domain can corrupt or panic any\nother node with a malformed message.  Three defects:\n\n  - dlm_migrate_request_handler() passes migrate-\u003enamelen unchecked to\n    dlm_init_mle(), which memcpy()s it into the 32-byte mname[] of an\n    o2dlm_mle slab object: a heap out-of-bounds write of up to ~215\n    attacker-controlled bytes.\n\n  - dlm_mig_lockres_handler() passes mres-\u003elockname_len unchecked to\n    dlm_init_lockres(), which memcpy()s it into the 32-byte o2dlm_lockname\n    slab object: a heap out-of-bounds write of up to ~223 bytes.\n\n  - the same handler trusts mres-\u003enum_locks without checking that the\n    message is large enough to hold that many entries, so\n    dlm_process_recovery_data() walks mres-\u003eml[] past the kmalloc(data_len)\n    copy and trips a BUG_ON (an out-of-bounds read ending in a panic).\n\nThe other o2dlm receive handlers already reject an oversized name; the\nmigration and recovery handlers have omitted it since the DLM was added\n(see the Fixes tags).  Patch 1 bounds namelen; patch 2 validates\nlockname_len, num_locks, and the payload size.  Conforming recovery and\nmigration traffic is unaffected.\n\no2net authenticates peers only by the DLM domain key, so any node that has\njoined the domain -- including a compromised or malicious member -- can\nsend these messages.  There is no local trigger; the attacker must already\nbe a member of the cluster.\n\nEach sink was confirmed under KASAN with an out-of-tree module mirroring\nit exactly -- a kmem_cache/kmalloc of the real destination size, then the\nsame unclamped memcpy/loop: slab-out-of-bounds Write for the two writes,\nRead for the recovery walk, and a panic.  A userspace AddressSanitizer\nbuild faults identically under -m32 and -m64.  Scrubbed logs are available\non request.\n\nI reported this privately to security@kernel.org and the ocfs2 maintainers\non 2026-06-20; with no response after the standard embargo period I am\nposting the fix publicly.  I have no embargo requirement.\n\n\nThis patch (of 2):\n\nA node receiving a DLM_MIGRATE_REQUEST message trusts the peer-supplied\nname length (migrate-\u003enamelen) without bounding it.  dlm_init_mle() then\ncopies that many bytes into the fixed DLM_LOCKID_NAME_MAX-byte mname[]\narray of an o2dlm_mle slab object, so a malformed message from a cluster\npeer overflows the slab object by up to ~215 bytes: a heap out-of-bounds\nwrite of attacker-controlled data, reachable by any node in the domain.\n\nReject an oversized name, the way dlm_master_request_handler() and the\nother o2dlm receive handlers already do; the migration handler omits the\ncheck entirely.  Conforming messages are unaffected.",
  "id": "CVE-2026-89495",
  "modified": "2026-09-13T03:30:52.284607633Z",
  "published": "2026-09-11T19:43:46.107Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2487bea2098322669f0563baff53e797486b823f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/de10cd3b062a5235af754925fcf49beb5a1109d4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ea5b5609305a8437bc955a0834a530c12246d78f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f8658ee3327f73bd81c0bcd07cdeb5a8527fac98"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89495.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89495"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "ocfs2: bound namelen in dlm_migrate_request_handler"
}