FKIE_CVE-2018-18955

Vulnerability from fkie_nvd - Published: 2018-11-16 20:29 - Updated: 2026-06-17 01:48
Severity
7.0 (High) - CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel 4.15.x through 4.19.x before 4.19.2, map_write() in kernel/user_namespace.c allows privilege escalation because it mishandles nested user namespaces with more than 5 UID or GID ranges. A user who has CAP_SYS_ADMIN in an affected user namespace can bypass access controls on resources outside the namespace, as demonstrated by reading /etc/shadow. This occurs because an ID transformation takes place properly for the namespaced-to-kernel direction but not for the kernel-to-namespaced direction.
References
cve@mitre.orghttp://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d2f007dbe7e4c9583eea6eb04d60001e85c6f1bdPatch, Vendor Advisory
cve@mitre.orghttp://www.securityfocus.com/bid/105941Third Party Advisory, VDB Entry
cve@mitre.orghttps://bugs.chromium.org/p/project-zero/issues/detail?id=1712Patch, Third Party Advisory
cve@mitre.orghttps://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.18.19Patch, Vendor Advisory
cve@mitre.orghttps://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.2Patch, Vendor Advisory
cve@mitre.orghttps://github.com/torvalds/linux/commit/d2f007dbe7e4c9583eea6eb04d60001e85c6f1bdPatch, Vendor Advisory
cve@mitre.orghttps://security.netapp.com/advisory/ntap-20190416-0003/
cve@mitre.orghttps://support.f5.com/csp/article/K39103040
cve@mitre.orghttps://usn.ubuntu.com/3832-1/Third Party Advisory
cve@mitre.orghttps://usn.ubuntu.com/3833-1/Third Party Advisory
cve@mitre.orghttps://usn.ubuntu.com/3835-1/Third Party Advisory
cve@mitre.orghttps://usn.ubuntu.com/3836-1/Third Party Advisory
cve@mitre.orghttps://usn.ubuntu.com/3836-2/Third Party Advisory
cve@mitre.orghttps://www.exploit-db.com/exploits/45886/Exploit, Patch, Third Party Advisory, VDB Entry
cve@mitre.orghttps://www.exploit-db.com/exploits/45915/Exploit, Third Party Advisory, VDB Entry
af854a3a-2127-422b-91ae-364da2661108http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d2f007dbe7e4c9583eea6eb04d60001e85c6f1bdPatch, Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108http://www.securityfocus.com/bid/105941Third Party Advisory, VDB Entry
af854a3a-2127-422b-91ae-364da2661108https://bugs.chromium.org/p/project-zero/issues/detail?id=1712Patch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.18.19Patch, Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.2Patch, Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/torvalds/linux/commit/d2f007dbe7e4c9583eea6eb04d60001e85c6f1bdPatch, Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108https://security.netapp.com/advisory/ntap-20190416-0003/
af854a3a-2127-422b-91ae-364da2661108https://support.f5.com/csp/article/K39103040
af854a3a-2127-422b-91ae-364da2661108https://usn.ubuntu.com/3832-1/Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://usn.ubuntu.com/3833-1/Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://usn.ubuntu.com/3835-1/Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://usn.ubuntu.com/3836-1/Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://usn.ubuntu.com/3836-2/Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://www.exploit-db.com/exploits/45886/Exploit, Patch, Third Party Advisory, VDB Entry
af854a3a-2127-422b-91ae-364da2661108https://www.exploit-db.com/exploits/45915/Exploit, Third Party Advisory, VDB Entry
Impacted products
Vendor Product Version
linux linux_kernel *
canonical ubuntu_linux 16.04
canonical ubuntu_linux 18.04
canonical ubuntu_linux 18.10
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "source": "cve@mitre.org"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "6572A2C1-2389-4DD6-A22F-40A8F0835AAB",
              "versionEndExcluding": "4.19.2",
              "versionStartIncluding": "4.15",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    },
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*",
              "matchCriteriaId": "F7016A2A-8365-4F1A-89A2-7A19F2BCAE5B",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*",
              "matchCriteriaId": "23A7C53F-B80F-4E6A-AFA9-58EEA84BE11D",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:canonical:ubuntu_linux:18.10:*:*:*:*:*:*:*",
              "matchCriteriaId": "07C312A0-CD2C-4B9C-B064-6409B25C278F",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel 4.15.x through 4.19.x before 4.19.2, map_write() in kernel/user_namespace.c allows privilege escalation because it mishandles nested user namespaces with more than 5 UID or GID ranges. A user who has CAP_SYS_ADMIN in an affected user namespace can bypass access controls on resources outside the namespace, as demonstrated by reading /etc/shadow. This occurs because an ID transformation takes place properly for the namespaced-to-kernel direction but not for the kernel-to-namespaced direction."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, de las versiones 4.15.x hasta las 4.19.x anteriores a la 4.19.2, map_write() en kernel/user_namespace.c permite el escalado de privilegios debido a que gestiona incorrectamente los espacios de nombre de usuario anidados con m\u00e1s de 5 rangos UID o GID. Un usuario que tenga CAP_SYS_ADMIN en un espacio de nombre de usuario afectado puede omitir los controles de acceso en los recursos fuera del espacio de nombre, tal y como queda demostrado con la lectura de /etc/shadow. Esto ocurre debido a que una transformaci\u00f3n ID ocurre correctamente para la direcci\u00f3n namespaced-to-kernel, pero no para la direcci\u00f3n kernel-to-namespaced."
    }
  ],
  "id": "CVE-2018-18955",
  "lastModified": "2026-06-17T01:48:10.833",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "MEDIUM",
        "cvssData": {
          "accessComplexity": "MEDIUM",
          "accessVector": "LOCAL",
          "authentication": "NONE",
          "availabilityImpact": "PARTIAL",
          "baseScore": 4.4,
          "confidentialityImpact": "PARTIAL",
          "integrityImpact": "PARTIAL",
          "vectorString": "AV:L/AC:M/Au:N/C:P/I:P/A:P",
          "version": "2.0"
        },
        "exploitabilityScore": 3.4,
        "impactScore": 6.4,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "nvd@nist.gov",
        "type": "Primary",
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV30": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.0,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.0"
        },
        "exploitabilityScore": 1.0,
        "impactScore": 5.9,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2018-11-16T20:29:00.233",
  "references": [
    {
      "source": "cve@mitre.org",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "url": "http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d2f007dbe7e4c9583eea6eb04d60001e85c6f1bd"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Third Party Advisory",
        "VDB Entry"
      ],
      "url": "http://www.securityfocus.com/bid/105941"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "url": "https://bugs.chromium.org/p/project-zero/issues/detail?id=1712"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "url": "https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.18.19"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "url": "https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.2"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "url": "https://github.com/torvalds/linux/commit/d2f007dbe7e4c9583eea6eb04d60001e85c6f1bd"
    },
    {
      "source": "cve@mitre.org",
      "url": "https://security.netapp.com/advisory/ntap-20190416-0003/"
    },
    {
      "source": "cve@mitre.org",
      "url": "https://support.f5.com/csp/article/K39103040"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://usn.ubuntu.com/3832-1/"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://usn.ubuntu.com/3833-1/"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://usn.ubuntu.com/3835-1/"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://usn.ubuntu.com/3836-1/"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://usn.ubuntu.com/3836-2/"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Exploit",
        "Patch",
        "Third Party Advisory",
        "VDB Entry"
      ],
      "url": "https://www.exploit-db.com/exploits/45886/"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Exploit",
        "Third Party Advisory",
        "VDB Entry"
      ],
      "url": "https://www.exploit-db.com/exploits/45915/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "url": "http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d2f007dbe7e4c9583eea6eb04d60001e85c6f1bd"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory",
        "VDB Entry"
      ],
      "url": "http://www.securityfocus.com/bid/105941"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "url": "https://bugs.chromium.org/p/project-zero/issues/detail?id=1712"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "url": "https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.18.19"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "url": "https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.2"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "url": "https://github.com/torvalds/linux/commit/d2f007dbe7e4c9583eea6eb04d60001e85c6f1bd"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "https://security.netapp.com/advisory/ntap-20190416-0003/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "https://support.f5.com/csp/article/K39103040"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://usn.ubuntu.com/3832-1/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://usn.ubuntu.com/3833-1/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://usn.ubuntu.com/3835-1/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://usn.ubuntu.com/3836-1/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://usn.ubuntu.com/3836-2/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Exploit",
        "Patch",
        "Third Party Advisory",
        "VDB Entry"
      ],
      "url": "https://www.exploit-db.com/exploits/45886/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Exploit",
        "Third Party Advisory",
        "VDB Entry"
      ],
      "url": "https://www.exploit-db.com/exploits/45915/"
    }
  ],
  "sourceIdentifier": "cve@mitre.org",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-863"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.