CriticalFix available

ksmbd: serialize QUERY_DIRECTORY requests per file

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: ksmbd: serialize QUERY_DIRECTORY requests per file smb2_query_dir() stores a pointer to its stack-allocated private data in the ksmbd_file readdir_data. Concurrent QUERY_DIRECTORY requests using the same file handle can overwrite this pointer while an iterate_dir() callback is still using it, resulting in a stack use-after-free. Add a per-file mutex and hold it while accessing the shared directory enumeration state. The lock covers scan restart, dot entry state, readdir_data setup and iteration, and response construction. This prevents another request from replacing readdir_data.private before the current request has finished using it and also serializes the shared file position.

Products: Kernel
Affected versions: Not specified
Fixed versions: 6.1.178, 6.12.96, 6.18.39, 6.6.145, 7.1.4
CVEs: CVE-2026-64397
Confirmed fixed CVEs: Not specified
Updated in this feed: 5 Nov 2026, 10:34 UTC · Revision 1

Source evidence

ksmbd: serialize QUERY_DIRECTORY requests per file

core-osv · Original source

Published 25 Jul 2026, 08:50 UTC

osv:CVE-2026-64397

Kernel

Fixed versions: 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4

Complete source record

{
  "id": "9586ba26e0538f6bb87edd74ca8b42cc930c0702b46bc955c54d2c0e0967f44d",
  "url": "https://osv.dev/vulnerability/CVE-2026-64397",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ksmbd: serialize QUERY_DIRECTORY requests per file",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ksmbd: serialize QUERY_DIRECTORY requests per file smb2_query_dir() stores a pointer to its stack-allocated private data in the ksmbd_file readdir_data. Concurrent QUERY_DIRECTORY requests using the same file handle can overwrite this pointer while an iterate_dir() callback is still using it, resulting in a stack use-after-free. Add a per-file mutex and hold it while accessing the shared directory enumeration state. The lock covers scan restart, dot entry state, readdir_data setup and iteration, and response construction. This prevents another request from replacing readdir_data.private before the current request has finished using it and also serializes the shared file position.",
    "evidence": "osv:CVE-2026-64397",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.178",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.145",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.96",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.39",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.4",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-64397",
      "aliases": [
        "CVE-2026-64397"
      ],
      "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": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9"
                },
                {
                  "fixed": "1426fd79102539bc0ab5c8fced047ad4313b9908"
                },
                {
                  "fixed": "2a64dbf9c739ddf7a25a066507597bf89f8f73d2"
                },
                {
                  "fixed": "64dac2d486ec1eb18dc00968b16a230b6b75ec24"
                },
                {
                  "fixed": "a1d5d31cad593ea5e1b637f2f39c9ef6d09d1199"
                },
                {
                  "fixed": "fd22b039a5a05bc1d6818e9dcd1001fb432a829d"
                },
                {
                  "fixed": "be6d26bf27499977c746abc163659915082348d8"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64397.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.15.0"
                },
                {
                  "fixed": "6.1.178"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.145"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.96"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.39"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.1.4"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64397.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:43.785476989Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1426fd79102539bc0ab5c8fced047ad4313b9908",
        "https://git.kernel.org/stable/c/2a64dbf9c739ddf7a25a066507597bf89f8f73d2",
        "https://git.kernel.org/stable/c/64dac2d486ec1eb18dc00968b16a230b6b75ec24",
        "https://git.kernel.org/stable/c/a1d5d31cad593ea5e1b637f2f39c9ef6d09d1199",
        "https://git.kernel.org/stable/c/be6d26bf27499977c746abc163659915082348d8",
        "https://git.kernel.org/stable/c/fd22b039a5a05bc1d6818e9dcd1001fb432a829d",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64397.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-64397",
        "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/2026/64xxx/CVE-2026-64397.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-64397",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 511638,
  "published_at": "2026-07-25T08:50:41.62+00:00"
}