CriticalFix available

ocfs2: validate lengths in dlm_mig_lockres_handler

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate lengths in dlm_mig_lockres_handler A node receiving a DLM_MIG_LOCKRES message trusts several fields of the peer-supplied dlm_migratable_lockres without validation. num_locks and lockname_len are bounded only on the sending side, and the message is never checked to actually carry num_locks migratable_lock entries. As a result dlm_process_recovery_data() walks mres->ml[0..num_locks) past the kmalloc(data_len) copy of the message (an out-of-bounds read that ends in a BUG_ON panic), and dlm_init_lockres() copies lockname_len bytes into the fixed 32-byte o2dlm_lockname slab object (a heap out-of-bounds write). Both are reachable by any node in the domain. Validate these fields right after dlm_grab(), before anything uses them -- including the not-joined error path, which already prints mres->lockname with the unbounded lockname_len as a %.*s precision. Reject the message unless lockname_len <= DLM_LOCKID_NAME_MAX, num_locks <= DLM_MAX_MIGRATABLE_LOCKS (the bound the sender already asserts), and the payload is large enough to hold the claimed locks. Conforming recovery and migration messages are unaffected.

Products: Kernel
Affected versions: Not specified
Fixed versions: 5.10.270, 5.15.221, 6.1.188, 6.12.109, 6.18.50, 6.6.157, 7.2.4
CVEs: CVE-2026-89494
Confirmed fixed CVEs: Not specified
Updated in this feed: 2 Nov 2026, 20:24 UTC · Revision 1

Source evidence

ocfs2: validate lengths in dlm_mig_lockres_handler

core-osv · Original source

Published 11 Sept 2026, 19:43 UTC

osv:CVE-2026-89494

Kernel

Fixed versions: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4

Complete source record

{
  "id": "245ea8a5ea0cd6efdcc486a0c3e7a18515d7f22298e65165a151c86830f7cbd4",
  "url": "https://osv.dev/vulnerability/CVE-2026-89494",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ocfs2: validate lengths in dlm_mig_lockres_handler",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate lengths in dlm_mig_lockres_handler A node receiving a DLM_MIG_LOCKRES message trusts several fields of the peer-supplied dlm_migratable_lockres without validation. num_locks and lockname_len are bounded only on the sending side, and the message is never checked to actually carry num_locks migratable_lock entries. As a result dlm_process_recovery_data() walks mres->ml[0..num_locks) past the kmalloc(data_len) copy of the message (an out-of-bounds read that ends in a BUG_ON panic), and dlm_init_lockres() copies lockname_len bytes into the fixed 32-byte o2dlm_lockname slab object (a heap out-of-bounds write). Both are reachable by any node in the domain. Validate these fields right after dlm_grab(), before anything uses them -- including the not-joined error path, which already prints mres->lockname with the unbounded lockname_len as a %.*s precision. Reject the message unless lockname_len <= DLM_LOCKID_NAME_MAX, num_locks <= DLM_MAX_MIGRATABLE_LOCKS (the bound the sender already asserts), and the payload is large enough to hold the claimed locks. Conforming recovery and migration messages are unaffected.",
    "evidence": "osv:CVE-2026-89494",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.270",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.221",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.188",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.157",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.109",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.50",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.4",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-89494",
      "aliases": [
        "CVE-2026-89494"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "6714d8e86bf443f6f7af50f9d432025649f091f5"
                },
                {
                  "fixed": "4a5798253212093b9ff7d90c6cfbe348bcda1594"
                },
                {
                  "fixed": "dce05b17db862f47ff60614017abe639b2e71cad"
                },
                {
                  "fixed": "0e999d56917f861f97adb961617b1828c9eb4733"
                },
                {
                  "fixed": "77686fa5bba135252d348e2dacf481fc19f60c41"
                },
                {
                  "fixed": "f33041906885f96e190cde54e61ddc69de39e3ee"
                },
                {
                  "fixed": "50c4cc9183e11f83427efbf770f54851f4471c02"
                },
                {
                  "fixed": "a8facb1670b4a0612183198e758d9539ef628ed9"
                },
                {
                  "fixed": "b54e03d9b3697d25f4a0063cf717d459c5e3ad94"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89494.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "2.6.16"
                },
                {
                  "fixed": "5.10.270"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.221"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.188"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.157"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "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"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89494.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:23.374246493Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/0e999d56917f861f97adb961617b1828c9eb4733",
        "https://git.kernel.org/stable/c/4a5798253212093b9ff7d90c6cfbe348bcda1594",
        "https://git.kernel.org/stable/c/50c4cc9183e11f83427efbf770f54851f4471c02",
        "https://git.kernel.org/stable/c/77686fa5bba135252d348e2dacf481fc19f60c41",
        "https://git.kernel.org/stable/c/a8facb1670b4a0612183198e758d9539ef628ed9",
        "https://git.kernel.org/stable/c/b54e03d9b3697d25f4a0063cf717d459c5e3ad94",
        "https://git.kernel.org/stable/c/dce05b17db862f47ff60614017abe639b2e71cad",
        "https://git.kernel.org/stable/c/f33041906885f96e190cde54e61ddc69de39e3ee",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89494.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-89494",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89494.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-89494",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 489811,
  "published_at": "2026-09-11T19:43:45.455+00:00"
}