CVE-2026-98451 (GCVE-0-2026-98451)
Vulnerability from cvelistv5
Published
2026-10-18 15:15
Modified
2026-10-24 14:08
Severity ?
8.8 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: use finish_no_open() for non-regular inodes An O_CREAT open can find an existing symlink or another non-regular inode. cifs_atomic_open() calls finish_open() on it and attaches a cifsFileInfo. Symlink inodes have no CIFS release operation, so the dentry reference held by cifsFileInfo is leaked. FMODE_OPENED also prevents the VFS from following the symlink. Track whether cifs_do_create() returned an open server handle. For non-regular inodes, close the handle if present, remove the pending open, and call finish_no_open() so the VFS can continue the lookup. Do not set FMODE_CREATED unless a regular file was opened. For O_NOFOLLOW with __O_REGULAR, return -ELOOP before the VFS's -EFTYPE check. Defer closing a legacy POSIX handle on a non-regular inode until after inode lookup. This avoids closing it again if lookup fails.
References
Impacted products
Vendor Product Version
Linux Linux Version: d2c127197dfc0b2bae62a52e1e0d3e3ff493919e
Version: d2c127197dfc0b2bae62a52e1e0d3e3ff493919e
Version: d2c127197dfc0b2bae62a52e1e0d3e3ff493919e
Version: d2c127197dfc0b2bae62a52e1e0d3e3ff493919e
Version: d2c127197dfc0b2bae62a52e1e0d3e3ff493919e
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/dir.c"
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          "programFiles": [
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "3.6"
            },
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              "lessThan": "3.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "version": "6.6.160",
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              "status": "unaffected",
              "version": "6.12.113",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.56",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.160",
                  "versionStartIncluding": "3.6",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "6.12.113",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: use finish_no_open() for non-regular inodes\n\nAn O_CREAT open can find an existing symlink or another non-regular\ninode. cifs_atomic_open() calls finish_open() on it and attaches a\ncifsFileInfo. Symlink inodes have no CIFS release operation, so the\ndentry reference held by cifsFileInfo is leaked. FMODE_OPENED also\nprevents the VFS from following the symlink.\n\nTrack whether cifs_do_create() returned an open server handle. For\nnon-regular inodes, close the handle if present, remove the pending\nopen, and call finish_no_open() so the VFS can continue the lookup.\nDo not set FMODE_CREATED unless a regular file was opened. For\nO_NOFOLLOW with __O_REGULAR, return -ELOOP before the VFS\u0027s\n-EFTYPE check.\n\nDefer closing a legacy POSIX handle on a non-regular inode until\nafter inode lookup. This avoids closing it again if lookup fails."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - `openat(O_CREAT)` reaches `cifs_atomic_open()` and `cifs_do_create()`; a remote SMB2 server can return a CREATE/reparse response identifying the object as `IO_REPARSE_TAG_LX_FIFO`, so the causative inode type arrives over routable SMB.\nAC:L - The server can return a FIFO for any fresh, uncached requested name; after the victim\u0027s O_CREAT, `finish_open()` and `cifs_new_fileinfo()` deterministically create the type confusion without a race or an uncontrollable precondition.\nPR:N - A malicious SMB endpoint needs no account or capability on the client; the SMB session authenticates the victim outward to the server, which directly controls the CREATE and reparse responses.\nUI:R - The remote server cannot initiate `cifs_atomic_open()` itself; a victim must mount or access its share and issue an O_CREAT open, after which the server can substitute the non-regular inode response.\nS:U - The confused `cifsFileInfo` and resulting pipe operations execute within the vulnerable client\u0027s kernel security authority and do not cross a VM, IOMMU, or other security boundary.\nC:H - `cifs_set_ops()` installs `pipefifo_fops`, but `finish_open(..., generic_file_open)` skips `fifo_open()` and `cifs_new_fileinfo()` puts a `cifsFileInfo` in `private_data`; `fifo_pipe_read()` then treats its fields as pipe buffers and pages, creating disclosure-capable type confusion.\nI:H - `pipe_release()` and `pipe_resize_ring()` treat the `cifsFileInfo` as `pipe_inode_info`, modifying fake mutex, counter, waitqueue, and buffer-pointer fields and potentially freeing the misinterpreted `pipe-\u003ebufs`, providing kernel-memory corruption primitives.\nA:H - Closing the returned FIFO fd invokes `pipe_release()` on the `cifsFileInfo`; locking its list pointers as a pipe mutex and accessing fake pipe state can immediately oops or hang the kernel, beyond the separate symlink reference leak."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-24T14:08:53.021Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/045532f920d86dd76600b635f9756e5fd671ddfc"
        },
        {
          "url": "https://git.kernel.org/stable/c/ed03d547598c92a036f20e89156540995cac889a"
        },
        {
          "url": "https://git.kernel.org/stable/c/70a7918fda54a06d836acc91eb9a3c7e860fe0a0"
        },
        {
          "url": "https://git.kernel.org/stable/c/3c07deb26273155c180aedfd9041ab58015d2521"
        },
        {
          "url": "https://git.kernel.org/stable/c/e66cf1625ec4a3fe68346119f371def713fd0a4d"
        }
      ],
      "title": "smb: client: use finish_no_open() for non-regular inodes",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98451",
    "datePublished": "2026-10-18T15:15:01.473Z",
    "dateReserved": "2026-09-25T10:25:14.350Z",
    "dateUpdated": "2026-10-24T14:08:53.021Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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