CVE-2026-98451 (GCVE-0-2026-98451)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:15 – Updated: 2026-10-24 14:08
VLAI
Title
smb: client: use finish_no_open() for non-regular inodes
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.
Severity
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7056 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: d2c127197dfc0b2bae62a52e1e0d3e3ff493919e , < 045532f920d86dd76600b635f9756e5fd671ddfc (git)
Affected: d2c127197dfc0b2bae62a52e1e0d3e3ff493919e , < ed03d547598c92a036f20e89156540995cac889a (git)
Affected: d2c127197dfc0b2bae62a52e1e0d3e3ff493919e , < 70a7918fda54a06d836acc91eb9a3c7e860fe0a0 (git)
Affected: d2c127197dfc0b2bae62a52e1e0d3e3ff493919e , < 3c07deb26273155c180aedfd9041ab58015d2521 (git)
Affected: d2c127197dfc0b2bae62a52e1e0d3e3ff493919e , < e66cf1625ec4a3fe68346119f371def713fd0a4d (git)
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Linux Linux Affected: 3.6
Unaffected: 0 , < 3.6 (semver)
Unaffected: 6.6.160 , ≤ 6.6.* (semver)
Unaffected: 6.12.113 , ≤ 6.12.* (semver)
Unaffected: 6.18.56 , ≤ 6.18.* (semver)
Unaffected: 7.2.9 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
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        {
          "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."
        }
      ],
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            "baseSeverity": "HIGH",
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            "version": "3.1"
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          "scenarios": [
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              "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."
            }
          ]
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      "providerMetadata": {
        "dateUpdated": "2026-10-24T14:08:53.021Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/045532f920d86dd76600b635f9756e5fd671ddfc"
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          "url": "https://git.kernel.org/stable/c/ed03d547598c92a036f20e89156540995cac889a"
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        {
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    "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"
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      "date": "2026-10-25",
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      "cve": "CVE-2026-98451",
      "id": "msrc_CVE-2026-98451",
      "initial_release_date": "2026-10-20T01:08:36.000Z",
      "product_status:known_affected": "1",
      "product_status:under_investigation": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "smb: client: use finish_no_open() for non-regular inodes",
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      "version": "3"
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          }
        ],
        "id": "CVE-2026-98451",
        "lastModified": "2026-10-24T14:16:42.393",
        "metrics": {
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                "attackVector": "NETWORK",
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                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "REQUIRED",
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      "cve": "CVE-2026-98451",
      "id": "CVE-2026-98451",
      "initial_release_date": "2026-10-18T00:00:00+00:00",
      "product_status:known_affected": "236",
      "product_status:known_not_affected": "42",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: smb: client: use finish_no_open() for non-regular inodes",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98451.json",
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      "current_release_date": "2026-10-20T23:50:54Z",
      "cve": "CVE-2026-98451",
      "id": "CVE-2026-98451",
      "initial_release_date": "2026-10-20T23:50:54Z",
      "product_status:known_affected": "158",
      "product_status:known_not_affected": "190",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-98451",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/2026/cve-2026-98451.json",
      "version": "2"
    }
  }
}



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