cifs: fix DFS traversal oops without CONFIG_CIFS_DFS_UPCALL

{
  "id": "b5aeecab252e43e4a15ff7a190327653bf72a0c345ce848822e7d155aac024c1",
  "url": "https://osv.dev/vulnerability/CVE-2023-53246",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "cifs: fix DFS traversal oops without CONFIG_CIFS_DFS_UPCALL",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: cifs: fix DFS traversal oops without CONFIG_CIFS_DFS_UPCALL When compiled with CONFIG_CIFS_DFS_UPCALL disabled, cifs_dfs_d_automount is NULL. cifs.ko logic for mapping CIFS_FATTR_DFS_REFERRAL attributes to S_AUTOMOUNT and corresponding dentry flags is retained regardless of CONFIG_CIFS_DFS_UPCALL, leading to a NULL pointer dereference in VFS follow_automount() when traversing a DFS referral link: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... Call Trace: __traverse_mounts+0xb5/0x220 ? cifs_revalidate_mapping+0x65/0xc0 [cifs] step_into+0x195/0x610 ? lookup_fast+0xe2/0xf0 path_lookupat+0x64/0x140 filename_lookup+0xc2/0x140 ? __create_object+0x299/0x380 ? kmem_cache_alloc+0x119/0x220 ? user_path_at_empty+0x31/0x50 user_path_at_empty+0x31/0x50 __x64_sys_chdir+0x2a/0xd0 ? exit_to_user_mode_prepare+0xca/0x100 do_syscall_64+0x42/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc This fix adds an inline cifs_dfs_d_automount() {return -EREMOTE} handler when CONFIG_CIFS_DFS_UPCALL is disabled. An alternative would be to avoid flagging S_AUTOMOUNT, etc. without CONFIG_CIFS_DFS_UPCALL. This approach was chosen as it provides more control over the error path.",
    "evidence": "osv:CVE-2023-53246",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.177",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.106",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.23",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.2.10",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2023-53246",
      "aliases": [
        "CVE-2023-53246"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "introduced": "25e195aa1e607f129ab912d29fcfc79239703307"
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                {
                  "fixed": "26a32a212bc540f4773cd6af8cf73e967d72569c"
                },
                {
                  "fixed": "b64305185b76f1d5145ce594ff48f3f0e70695bd"
                },
                {
                  "fixed": "b7d854c33ab48e55fc233699bbefe39ec9bb5c05"
                },
                {
                  "fixed": "1e144b68208e98fd4602c842a7149ba5f41d87fb"
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                {
                  "fixed": "179a88a8558bbf42991d361595281f3e45d7edfc"
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53246.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.7.0"
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                {
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            {
              "type": "ECOSYSTEM",
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                  "fixed": "5.15.106"
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              "events": [
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                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.23"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.2.10"
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              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53246.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:49.226721184Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/179a88a8558bbf42991d361595281f3e45d7edfc",
        "https://git.kernel.org/stable/c/1e144b68208e98fd4602c842a7149ba5f41d87fb",
        "https://git.kernel.org/stable/c/26a32a212bc540f4773cd6af8cf73e967d72569c",
        "https://git.kernel.org/stable/c/b64305185b76f1d5145ce594ff48f3f0e70695bd",
        "https://git.kernel.org/stable/c/b7d854c33ab48e55fc233699bbefe39ec9bb5c05",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53246.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-53246",
        "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/2023/53xxx/CVE-2023-53246.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-53246",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 517280,
  "published_at": "2025-09-15T14:46:15.977+00:00"
}