CVE-2026-64388 (GCVE-0-2026-64388)
Vulnerability from cvelistv5
Published
2026-07-25 08:50
Modified
2026-10-21 12:43
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: smb/client: fix chown/chgrp with SMB3 POSIX Extensions Ownership (chown) and group (chgrp) modifications were being ignored when mounting with SMB3 POSIX Extensions unless CIFS_MOUNT_CIFS_ACL or CIFS_MOUNT_MODE_FROM_SID were also explicitly set. Fix this by checking for posix_extensions in cifs_setattr_nounix() when updating UID and GID, ensuring that id_mode_to_cifs_acl() is called to map and set the ownership/group information on the server.
References
Impacted products
Vendor Product Version
Linux Linux Version: b326614ea2159ea5c835d320f261d05d080cd201
Version: b326614ea2159ea5c835d320f261d05d080cd201
Version: b326614ea2159ea5c835d320f261d05d080cd201
Version: b326614ea2159ea5c835d320f261d05d080cd201
Version: b326614ea2159ea5c835d320f261d05d080cd201
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-64388",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-16T15:40:07.284651Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-682",
                "description": "CWE-682 Incorrect Calculation",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-19T20:38:26.851Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/inode.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6825a45f6b8ef76b0ee32649ec3d6e39ca143a18",
              "status": "affected",
              "version": "b326614ea2159ea5c835d320f261d05d080cd201",
              "versionType": "git"
            },
            {
              "lessThan": "27ead8c5418af6bfab711079fecb9414d78d4cae",
              "status": "affected",
              "version": "b326614ea2159ea5c835d320f261d05d080cd201",
              "versionType": "git"
            },
            {
              "lessThan": "3eaec47518e126e6dcd1a48521d740278073f0ec",
              "status": "affected",
              "version": "b326614ea2159ea5c835d320f261d05d080cd201",
              "versionType": "git"
            },
            {
              "lessThan": "550cfb8a81181331d4d0f76ab75ee58a0bf41e3e",
              "status": "affected",
              "version": "b326614ea2159ea5c835d320f261d05d080cd201",
              "versionType": "git"
            },
            {
              "lessThan": "760ef2c579c2609cf17fb1cd5392f64d42d43d33",
              "status": "affected",
              "version": "b326614ea2159ea5c835d320f261d05d080cd201",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/inode.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.18"
            },
            {
              "lessThan": "4.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.114",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.57",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "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": "6.6.160",
                  "versionStartIncluding": "4.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.114",
                  "versionStartIncluding": "4.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.57",
                  "versionStartIncluding": "4.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.4",
                  "versionStartIncluding": "4.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "4.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb/client: fix chown/chgrp with SMB3 POSIX Extensions\n\nOwnership (chown) and group (chgrp) modifications were being ignored when\nmounting with SMB3 POSIX Extensions unless CIFS_MOUNT_CIFS_ACL or\nCIFS_MOUNT_MODE_FROM_SID were also explicitly set.\n\nFix this by checking for posix_extensions in cifs_setattr_nounix() when\nupdating UID and GID, ensuring that id_mode_to_cifs_acl() is called to map\nand set the ownership/group information on the server."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable branch is reached through local chown/chgrp syscalls on an already mounted SMB3 POSIX share; unsolicited SMB traffic cannot invoke it.\nAC:L - With the affected mount configuration, the client deterministically skips the ownership update and returns success; no race, heap layout, or uncontrollable timing is required.\nPR:L - A basic local user can exercise the path on accessible share objects, and noperm deliberately defers authorization to the server whose ownership check is bypassed because no request is sent. The attacker need not create the mount.\nUI:N - The attacker can invoke the syscall directly and exploit continued rights or falsely cached ownership through automated services without human action.\nS:U - The defect affects resources governed through the vulnerable kernel and mounted share without escaping a VM, sandbox, or other distinct security authority.\nC:H - Because the intended ownership change never reaches the server, the prior owner or group can retain read access to an entire data tree believed to have been transferred or revoked.\nI:H - The prior owner can retain arbitrary modification rights, while falsely cached privileged ownership can cause privileged consumers to trust or execute attacker-controlled content.\nA:H - Retained ownership of writable files or directories can permit truncation or deletion of an entire service data tree, and privileged execution through false ownership can cause a complete outage."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:43:18.915Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6825a45f6b8ef76b0ee32649ec3d6e39ca143a18"
        },
        {
          "url": "https://git.kernel.org/stable/c/27ead8c5418af6bfab711079fecb9414d78d4cae"
        },
        {
          "url": "https://git.kernel.org/stable/c/3eaec47518e126e6dcd1a48521d740278073f0ec"
        },
        {
          "url": "https://git.kernel.org/stable/c/550cfb8a81181331d4d0f76ab75ee58a0bf41e3e"
        },
        {
          "url": "https://git.kernel.org/stable/c/760ef2c579c2609cf17fb1cd5392f64d42d43d33"
        }
      ],
      "title": "smb/client: fix chown/chgrp with SMB3 POSIX Extensions",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64388",
    "datePublished": "2026-07-25T08:50:36.202Z",
    "dateReserved": "2026-07-19T15:36:31.784Z",
    "dateUpdated": "2026-10-21T12:43:18.915Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-64388\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-10-16T15:40:07.284651Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-682\", \"description\": \"CWE-682 Incorrect Calculation\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-10-16T15:40:08.065Z\"}}], \"cna\": {\"title\": \"smb/client: fix chown/chgrp with SMB3 POSIX Extensions\", \"metrics\": [{\"cvssV3_1\": {\"version\": \"3.1\", \"baseScore\": 7.8, \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"AV:L - The vulnerable branch is reached through local chown/chgrp syscalls on an already mounted SMB3 POSIX share; unsolicited SMB traffic cannot invoke it.\\nAC:L - With the affected mount configuration, the client deterministically skips the ownership update and returns success; no race, heap layout, or uncontrollable timing is required.\\nPR:L - A basic local user can exercise the path on accessible share objects, and noperm deliberately defers authorization to the server whose ownership check is bypassed because no request is sent. The attacker need not create the mount.\\nUI:N - The attacker can invoke the syscall directly and exploit continued rights or falsely cached ownership through automated services without human action.\\nS:U - The defect affects resources governed through the vulnerable kernel and mounted share without escaping a VM, sandbox, or other distinct security authority.\\nC:H - Because the intended ownership change never reaches the server, the prior owner or group can retain read access to an entire data tree believed to have been transferred or revoked.\\nI:H - The prior owner can retain arbitrary modification rights, while falsely cached privileged ownership can cause privileged consumers to trust or execute attacker-controlled content.\\nA:H - Retained ownership of writable files or directories can permit truncation or deletion of an entire service data tree, and privileged execution through false ownership can cause a complete outage.\"}]}], \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"b326614ea2159ea5c835d320f261d05d080cd201\", \"lessThan\": \"6825a45f6b8ef76b0ee32649ec3d6e39ca143a18\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"b326614ea2159ea5c835d320f261d05d080cd201\", \"lessThan\": \"27ead8c5418af6bfab711079fecb9414d78d4cae\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"b326614ea2159ea5c835d320f261d05d080cd201\", \"lessThan\": \"3eaec47518e126e6dcd1a48521d740278073f0ec\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"b326614ea2159ea5c835d320f261d05d080cd201\", \"lessThan\": \"550cfb8a81181331d4d0f76ab75ee58a0bf41e3e\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"b326614ea2159ea5c835d320f261d05d080cd201\", \"lessThan\": \"760ef2c579c2609cf17fb1cd5392f64d42d43d33\", \"versionType\": \"git\"}], \"programFiles\": [\"fs/smb/client/inode.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"4.18\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"4.18\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"6.6.160\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.6.*\"}, {\"status\": \"unaffected\", \"version\": \"6.12.114\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.12.*\"}, {\"status\": \"unaffected\", \"version\": \"6.18.57\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.18.*\"}, {\"status\": \"unaffected\", \"version\": \"7.1.4\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"7.1.*\"}, {\"status\": \"unaffected\", \"version\": \"7.2\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"fs/smb/client/inode.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/6825a45f6b8ef76b0ee32649ec3d6e39ca143a18\"}, {\"url\": \"https://git.kernel.org/stable/c/27ead8c5418af6bfab711079fecb9414d78d4cae\"}, {\"url\": \"https://git.kernel.org/stable/c/3eaec47518e126e6dcd1a48521d740278073f0ec\"}, {\"url\": \"https://git.kernel.org/stable/c/550cfb8a81181331d4d0f76ab75ee58a0bf41e3e\"}, {\"url\": \"https://git.kernel.org/stable/c/760ef2c579c2609cf17fb1cd5392f64d42d43d33\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nsmb/client: fix chown/chgrp with SMB3 POSIX Extensions\\n\\nOwnership (chown) and group (chgrp) modifications were being ignored when\\nmounting with SMB3 POSIX Extensions unless CIFS_MOUNT_CIFS_ACL or\\nCIFS_MOUNT_MODE_FROM_SID were also explicitly set.\\n\\nFix this by checking for posix_extensions in cifs_setattr_nounix() when\\nupdating UID and GID, ensuring that id_mode_to_cifs_acl() is called to map\\nand set the ownership/group information on the server.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.6.160\", \"versionStartIncluding\": \"4.18\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.12.114\", \"versionStartIncluding\": \"4.18\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.18.57\", \"versionStartIncluding\": \"4.18\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"7.1.4\", \"versionStartIncluding\": \"4.18\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"7.2\", \"versionStartIncluding\": \"4.18\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-10-21T12:43:18.915Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-64388\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-10-21T12:43:18.915Z\", \"dateReserved\": \"2026-07-19T15:36:31.784Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2026-07-25T08:50:36.202Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.