ubuntu-cve-2018-6954
Vulnerability from osv_ubuntu
Published
2018-02-13 00:00
Modified
2026-04-22 07:38
Summary
Details

systemd-tmpfiles in systemd through 237 mishandles symlinks present in non-terminal path components, which allows local users to obtain ownership of arbitrary files via vectors involving creation of a directory and a file under that directory, and later replacing that directory with a symlink. This occurs even if the fs.protected_symlinks sysctl is turned on.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8 (High)
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libnss-myhostname",
            "binary_version": "229-4ubuntu21.15"
          },
          {
            "binary_name": "libnss-mymachines",
            "binary_version": "229-4ubuntu21.15"
          },
          {
            "binary_name": "libnss-resolve",
            "binary_version": "229-4ubuntu21.15"
          },
          {
            "binary_name": "libpam-systemd",
            "binary_version": "229-4ubuntu21.15"
          },
          {
            "binary_name": "libsystemd0",
            "binary_version": "229-4ubuntu21.15"
          },
          {
            "binary_name": "libudev1",
            "binary_version": "229-4ubuntu21.15"
          },
          {
            "binary_name": "systemd",
            "binary_version": "229-4ubuntu21.15"
          },
          {
            "binary_name": "systemd-container",
            "binary_version": "229-4ubuntu21.15"
          },
          {
            "binary_name": "systemd-coredump",
            "binary_version": "229-4ubuntu21.15"
          },
          {
            "binary_name": "systemd-journal-remote",
            "binary_version": "229-4ubuntu21.15"
          },
          {
            "binary_name": "systemd-sysv",
            "binary_version": "229-4ubuntu21.15"
          },
          {
            "binary_name": "udev",
            "binary_version": "229-4ubuntu21.15"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "systemd",
        "purl": "pkg:deb/ubuntu/systemd@229-4ubuntu21.15?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "229-4ubuntu21.15"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "225-1ubuntu9",
        "227-2ubuntu1",
        "227-2ubuntu2",
        "228-1ubuntu2",
        "228-2ubuntu1",
        "228-2ubuntu2",
        "228-3ubuntu1",
        "228-4ubuntu1",
        "228-4ubuntu2",
        "228-5ubuntu1",
        "228-5ubuntu2",
        "228-5ubuntu3",
        "228-6ubuntu1",
        "229-1ubuntu2",
        "229-1ubuntu4",
        "229-2ubuntu1",
        "229-3ubuntu1",
        "229-3ubuntu2",
        "229-4ubuntu1",
        "229-4ubuntu4",
        "229-4ubuntu5",
        "229-4ubuntu6",
        "229-4ubuntu7",
        "229-4ubuntu8",
        "229-4ubuntu10",
        "229-4ubuntu11",
        "229-4ubuntu12",
        "229-4ubuntu13",
        "229-4ubuntu16",
        "229-4ubuntu17",
        "229-4ubuntu19",
        "229-4ubuntu20",
        "229-4ubuntu21",
        "229-4ubuntu21.1",
        "229-4ubuntu21.2",
        "229-4ubuntu21.3",
        "229-4ubuntu21.4",
        "229-4ubuntu21.5",
        "229-4ubuntu21.6",
        "229-4ubuntu21.8",
        "229-4ubuntu21.9",
        "229-4ubuntu21.10"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libnss-myhostname",
            "binary_version": "237-3ubuntu10.9"
          },
          {
            "binary_name": "libnss-mymachines",
            "binary_version": "237-3ubuntu10.9"
          },
          {
            "binary_name": "libnss-resolve",
            "binary_version": "237-3ubuntu10.9"
          },
          {
            "binary_name": "libnss-systemd",
            "binary_version": "237-3ubuntu10.9"
          },
          {
            "binary_name": "libpam-systemd",
            "binary_version": "237-3ubuntu10.9"
          },
          {
            "binary_name": "libsystemd0",
            "binary_version": "237-3ubuntu10.9"
          },
          {
            "binary_name": "libudev1",
            "binary_version": "237-3ubuntu10.9"
          },
          {
            "binary_name": "systemd",
            "binary_version": "237-3ubuntu10.9"
          },
          {
            "binary_name": "systemd-container",
            "binary_version": "237-3ubuntu10.9"
          },
          {
            "binary_name": "systemd-coredump",
            "binary_version": "237-3ubuntu10.9"
          },
          {
            "binary_name": "systemd-journal-remote",
            "binary_version": "237-3ubuntu10.9"
          },
          {
            "binary_name": "systemd-sysv",
            "binary_version": "237-3ubuntu10.9"
          },
          {
            "binary_name": "systemd-tests",
            "binary_version": "237-3ubuntu10.9"
          },
          {
            "binary_name": "udev",
            "binary_version": "237-3ubuntu10.9"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "systemd",
        "purl": "pkg:deb/ubuntu/systemd@237-3ubuntu10.9?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "237-3ubuntu10.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "234-2ubuntu12",
        "235-2ubuntu3",
        "235-3ubuntu2",
        "235-3ubuntu3",
        "237-3ubuntu3",
        "237-3ubuntu4",
        "237-3ubuntu6",
        "237-3ubuntu7",
        "237-3ubuntu8",
        "237-3ubuntu10",
        "237-3ubuntu10.2",
        "237-3ubuntu10.3",
        "237-3ubuntu10.4",
        "237-3ubuntu10.6"
      ]
    }
  ],
  "aliases": [],
  "details": "systemd-tmpfiles in systemd through 237 mishandles symlinks present in non-terminal path components, which allows local users to obtain ownership of arbitrary files via vectors involving creation of a directory and a file under that directory, and later replacing that directory with a symlink. This occurs even if the fs.protected_symlinks sysctl is turned on.",
  "id": "UBUNTU-CVE-2018-6954",
  "modified": "2026-04-22T07:38:34Z",
  "published": "2018-02-13T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2018-6954"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-3816-1"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-3816-2"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2018-6954"
    }
  ],
  "related": [
    "USN-3816-1",
    "USN-3816-2"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2018-6954"
  ]
}



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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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