Vulnerability-Lookup

FKIE_CVE-2026-68083

Vulnerability from fkie_nvd - Published: 2026-08-10 12:17 - Updated: 2026-08-17 05:18

Severity

9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix path resolution in ksmbd_vfs_kern_path_create The SMB2 open lookup is rooted at the share with LOOKUP_BENEATH, but the create/mkdir/hardlink sink is not: ksmbd_vfs_kern_path_create() builds an absolute path with convert_to_unix_name() and resolves it from AT_FDCWD via start_creating_path(), so a ".." component is walked from the real filesystem root and escapes the export. An authenticated client races a missing path component so the rooted open lookup returns -ENOENT (taking the create branch) while the same component is present (a directory) when the create walk runs; the create then resolves ".." out of the share. Root the create walk at the share like the lookup and rename paths already are: resolve the parent with vfs_path_parent_lookup(..., LOOKUP_BENEATH, &share_conf->vfs_path) and create the final component with start_creating_noperm(). convert_to_unix_name() then has no callers and is removed.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/1c8951963d8ed357f70f59e0ad4ddce2199d2016
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/489d1ded01425c0fb33418172c0e4e588467526b
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/98185b3025beeae92d1fe700d5db26b9ac4bf025
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/c7c884a1305aa4540eb7942a50bd356b34120e1f

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/misc.c",
            "fs/smb/server/misc.h",
            "fs/smb/server/vfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "489d1ded01425c0fb33418172c0e4e588467526b",
              "status": "affected",
              "version": "265fd1991c1db85fbabaad4946ca0e63e2ae688d",
              "versionType": "git"
            },
            {
              "lessThan": "c7c884a1305aa4540eb7942a50bd356b34120e1f",
              "status": "affected",
              "version": "265fd1991c1db85fbabaad4946ca0e63e2ae688d",
              "versionType": "git"
            },
            {
              "lessThan": "98185b3025beeae92d1fe700d5db26b9ac4bf025",
              "status": "affected",
              "version": "265fd1991c1db85fbabaad4946ca0e63e2ae688d",
              "versionType": "git"
            },
            {
              "lessThan": "1c8951963d8ed357f70f59e0ad4ddce2199d2016",
              "status": "affected",
              "version": "265fd1991c1db85fbabaad4946ca0e63e2ae688d",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/misc.c",
            "fs/smb/server/misc.h",
            "fs/smb/server/vfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix path resolution in ksmbd_vfs_kern_path_create\n\nThe SMB2 open lookup is rooted at the share with LOOKUP_BENEATH, but the\ncreate/mkdir/hardlink sink is not: ksmbd_vfs_kern_path_create() builds an\nabsolute path with convert_to_unix_name() and resolves it from AT_FDCWD\nvia start_creating_path(), so a \"..\" component is walked from the real\nfilesystem root and escapes the export.\n\nAn authenticated client races a missing path component so the rooted open\nlookup returns -ENOENT (taking the create branch) while the same component\nis present (a directory) when the create walk runs; the create then\nresolves \"..\" out of the share.\n\nRoot the create walk at the share like the lookup and rename paths already\nare: resolve the parent with vfs_path_parent_lookup(..., LOOKUP_BENEATH,\n\u0026share_conf-\u003evfs_path) and create the final component with\nstart_creating_noperm(). convert_to_unix_name() then has no callers and is\nremoved."
    }
  ],
  "id": "CVE-2026-68083",
  "lastModified": "2026-08-17T05:18:07.487",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.1,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.2,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-10T12:17:20.807",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1c8951963d8ed357f70f59e0ad4ddce2199d2016"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/489d1ded01425c0fb33418172c0e4e588467526b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/98185b3025beeae92d1fe700d5db26b9ac4bf025"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c7c884a1305aa4540eb7942a50bd356b34120e1f"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-68083 (GCVE-0-2026-68083)

Vulnerability from cvelistv5 – Published: 2026-08-10 11:41 – Updated: 2026-08-17 04:58

Title

ksmbd: fix path resolution in ksmbd_vfs_kern_path_create

Summary

Severity

9.1 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/489d1ded01425c0fb…
https://git.kernel.org/stable/c/c7c884a1305aa4540…
https://git.kernel.org/stable/c/98185b3025beeae92…
https://git.kernel.org/stable/c/1c8951963d8ed357f…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 265fd1991c1db85fbabaad4946ca0e63e2ae688d , < 489d1ded01425c0fb33418172c0e4e588467526b (git) Affected: 265fd1991c1db85fbabaad4946ca0e63e2ae688d , < c7c884a1305aa4540eb7942a50bd356b34120e1f (git) Affected: 265fd1991c1db85fbabaad4946ca0e63e2ae688d , < 98185b3025beeae92d1fe700d5db26b9ac4bf025 (git) Affected: 265fd1991c1db85fbabaad4946ca0e63e2ae688d , < 1c8951963d8ed357f70f59e0ad4ddce2199d2016 (git)
Linux	Linux	Affected: 5.15 Unaffected: 0 , < 5.15 (semver) Unaffected: 6.12.97 , ≤ 6.12.* (semver) Unaffected: 6.18.40 , ≤ 6.18.* (semver) Unaffected: 7.1.5 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/misc.c",
            "fs/smb/server/misc.h",
            "fs/smb/server/vfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "489d1ded01425c0fb33418172c0e4e588467526b",
              "status": "affected",
              "version": "265fd1991c1db85fbabaad4946ca0e63e2ae688d",
              "versionType": "git"
            },
            {
              "lessThan": "c7c884a1305aa4540eb7942a50bd356b34120e1f",
              "status": "affected",
              "version": "265fd1991c1db85fbabaad4946ca0e63e2ae688d",
              "versionType": "git"
            },
            {
              "lessThan": "98185b3025beeae92d1fe700d5db26b9ac4bf025",
              "status": "affected",
              "version": "265fd1991c1db85fbabaad4946ca0e63e2ae688d",
              "versionType": "git"
            },
            {
              "lessThan": "1c8951963d8ed357f70f59e0ad4ddce2199d2016",
              "status": "affected",
              "version": "265fd1991c1db85fbabaad4946ca0e63e2ae688d",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/misc.c",
            "fs/smb/server/misc.h",
            "fs/smb/server/vfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.97",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix path resolution in ksmbd_vfs_kern_path_create\n\nThe SMB2 open lookup is rooted at the share with LOOKUP_BENEATH, but the\ncreate/mkdir/hardlink sink is not: ksmbd_vfs_kern_path_create() builds an\nabsolute path with convert_to_unix_name() and resolves it from AT_FDCWD\nvia start_creating_path(), so a \"..\" component is walked from the real\nfilesystem root and escapes the export.\n\nAn authenticated client races a missing path component so the rooted open\nlookup returns -ENOENT (taking the create branch) while the same component\nis present (a directory) when the create walk runs; the create then\nresolves \"..\" out of the share.\n\nRoot the create walk at the share like the lookup and rename paths already\nare: resolve the parent with vfs_path_parent_lookup(..., LOOKUP_BENEATH,\n\u0026share_conf-\u003evfs_path) and create the final component with\nstart_creating_noperm(). convert_to_unix_name() then has no callers and is\nremoved."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.1,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - ksmbd is the in-kernel SMB server on TCP/445; the flaw is reached from remote SMB2_CREATE (and SMB2_SET_INFO hardlink) requests processed in ksmbd_conn_handler_loop() through smb2_open()/smb2_create_link() into ksmbd_vfs_kern_path_create().\nAC:L - Exploitation requires a TOCTOU race, but the attacker controls both sides by issuing concurrent SMB2_CREATE and directory-creation requests over one or more connections, so success does not depend on conditions outside attacker influence.\nPR:N - SMB2_CREATE requires a valid session, tree connect, and writable share, but ksmbd supports guest/anonymous sessions on writable exports; per kernel CNA precedent, export write access alone is not elevated privilege.\nUI:N - No victim interaction is required; the attacker sends crafted SMB2 protocol requests directly to a reachable ksmbd service without needing another user to mount shares or open files.\nS:U - Impact is confined to the host kernel filesystem namespace managed by ksmbd; escaping an SMB export is not a VM, IOMMU, or separate security-authority boundary crossing.\nC:N - This is a path-resolution logic flaw with no memory corruption, out-of-bounds access, or demonstrated arbitrary read of host files outside the export; impact is unauthorized creation/linking, not information disclosure.\nI:H - ksmbd_vfs_kern_path_create() resolves attacker paths from AT_FDCWD without LOOKUP_BENEATH, letting authenticated clients create files, directories, or hardlinks outside the exported share using the server\u0027s filesystem credentials.\nA:H - Repeated successful escaped creates/mkdirs outside the export can exhaust root-filesystem inodes or storage (especially tmpfs/world-writable targets), causing system-wide service unavailability on affected NAS/cloud hosts."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T04:58:30.819Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/489d1ded01425c0fb33418172c0e4e588467526b"
        },
        {
          "url": "https://git.kernel.org/stable/c/c7c884a1305aa4540eb7942a50bd356b34120e1f"
        },
        {
          "url": "https://git.kernel.org/stable/c/98185b3025beeae92d1fe700d5db26b9ac4bf025"
        },
        {
          "url": "https://git.kernel.org/stable/c/1c8951963d8ed357f70f59e0ad4ddce2199d2016"
        }
      ],
      "title": "ksmbd: fix path resolution in ksmbd_vfs_kern_path_create",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68083",
    "datePublished": "2026-08-10T11:41:47.153Z",
    "dateReserved": "2026-07-30T09:28:09.367Z",
    "dateUpdated": "2026-08-17T04:58:30.819Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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FKIE_CVE-2026-68083

CVE-2026-68083 (GCVE-0-2026-68083)

Tags

Sightings

Nomenclature

Related by attack behaviour