ubuntu-cve-2018-20021
Vulnerability from osv_ubuntu
Published
2018-12-19 00:00
Modified
2026-05-20 14:50
Summary
Details

LibVNC before commit c3115350eb8bb635d0fdb4dbbb0d0541f38ed19c contains a CWE-835: Infinite loop vulnerability in VNC client code. Vulnerability allows attacker to consume excessive amount of resources like CPU and RAM

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

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libvncserver-config",
            "binary_version": "0.9.9+dfsg-1ubuntu1.4"
          },
          {
            "binary_name": "libvncserver0",
            "binary_version": "0.9.9+dfsg-1ubuntu1.4"
          },
          {
            "binary_name": "linuxvnc",
            "binary_version": "0.9.9+dfsg-1ubuntu1.4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:14.04:LTS",
        "name": "libvncserver",
        "purl": "pkg:deb/ubuntu/libvncserver@0.9.9+dfsg-1ubuntu1.4?arch=source\u0026distro=trusty"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.9.9+dfsg-1ubuntu1.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9.9+dfsg-1",
        "0.9.9+dfsg-1ubuntu1",
        "0.9.9+dfsg-1ubuntu1.1",
        "0.9.9+dfsg-1ubuntu1.2",
        "0.9.9+dfsg-1ubuntu1.3"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "tightvncserver",
            "binary_version": "1.3.9-6.5+deb8u1build0.14.04.1~esm1"
          },
          {
            "binary_name": "xtightvncviewer",
            "binary_version": "1.3.9-6.5+deb8u1build0.14.04.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:14.04:LTS",
        "name": "tightvnc",
        "purl": "pkg:deb/ubuntu/tightvnc@1.3.9-6.5+deb8u1build0.14.04.1~esm1?arch=source\u0026distro=trusty/esm"
      },
      "ranges": [
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            },
            {
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            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.3.9-6.4",
        "1.3.9-6.4ubuntu1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "italc-client",
            "binary_version": "1:2.0.2+dfsg1-4ubuntu0.1"
          },
          {
            "binary_name": "italc-management-console",
            "binary_version": "1:2.0.2+dfsg1-4ubuntu0.1"
          },
          {
            "binary_name": "italc-master",
            "binary_version": "1:2.0.2+dfsg1-4ubuntu0.1"
          },
          {
            "binary_name": "libitalccore",
            "binary_version": "1:2.0.2+dfsg1-4ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "italc",
        "purl": "pkg:deb/ubuntu/italc@1:2.0.2+dfsg1-4ubuntu0.1?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
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            {
              "fixed": "1:2.0.2+dfsg1-4ubuntu0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:2.0.2+dfsg1-3",
        "1:2.0.2+dfsg1-4"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libvncclient1",
            "binary_version": "0.9.10+dfsg-3ubuntu0.16.04.3"
          },
          {
            "binary_name": "libvncserver-config",
            "binary_version": "0.9.10+dfsg-3ubuntu0.16.04.3"
          },
          {
            "binary_name": "libvncserver1",
            "binary_version": "0.9.10+dfsg-3ubuntu0.16.04.3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "libvncserver",
        "purl": "pkg:deb/ubuntu/libvncserver@0.9.10+dfsg-3ubuntu0.16.04.3?arch=source\u0026distro=xenial"
      },
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        {
          "events": [
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              "introduced": "0"
            },
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            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9.10+dfsg-3",
        "0.9.10+dfsg-3build1",
        "0.9.10+dfsg-3ubuntu0.16.04.1",
        "0.9.10+dfsg-3ubuntu0.16.04.2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "ssvnc",
            "binary_version": "1.0.29-2+deb8u1build0.16.04.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "ssvnc",
        "purl": "pkg:deb/ubuntu/ssvnc@1.0.29-2+deb8u1build0.16.04.1?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
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            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.0.29-2build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "tightvncserver",
            "binary_version": "1.3.10-0ubuntu3"
          },
          {
            "binary_name": "xtightvncviewer",
            "binary_version": "1.3.10-0ubuntu3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "tightvnc",
        "purl": "pkg:deb/ubuntu/tightvnc@1.3.10-0ubuntu3?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.3.10-0ubuntu2",
        "1.3.10-0ubuntu3"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "italc-client",
            "binary_version": "1:3.0.3+dfsg1-3ubuntu0.1"
          },
          {
            "binary_name": "italc-management-console",
            "binary_version": "1:3.0.3+dfsg1-3ubuntu0.1"
          },
          {
            "binary_name": "italc-master",
            "binary_version": "1:3.0.3+dfsg1-3ubuntu0.1"
          },
          {
            "binary_name": "libitalccore",
            "binary_version": "1:3.0.3+dfsg1-3ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "italc",
        "purl": "pkg:deb/ubuntu/italc@1:3.0.3+dfsg1-3ubuntu0.1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:3.0.3+dfsg1-3ubuntu0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:3.0.3+dfsg1-1",
        "1:3.0.3+dfsg1-2",
        "1:3.0.3+dfsg1-2build1",
        "1:3.0.3+dfsg1-2ubuntu1",
        "1:3.0.3+dfsg1-3"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libvncclient1",
            "binary_version": "0.9.11+dfsg-1ubuntu1.1"
          },
          {
            "binary_name": "libvncserver-config",
            "binary_version": "0.9.11+dfsg-1ubuntu1.1"
          },
          {
            "binary_name": "libvncserver1",
            "binary_version": "0.9.11+dfsg-1ubuntu1.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "libvncserver",
        "purl": "pkg:deb/ubuntu/libvncserver@0.9.11+dfsg-1ubuntu1.1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.9.11+dfsg-1ubuntu1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9.11+dfsg-1",
        "0.9.11+dfsg-1ubuntu1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "ssvnc",
            "binary_version": "1.0.29-3build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "ssvnc",
        "purl": "pkg:deb/ubuntu/ssvnc@1.0.29-3build1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.0.29-3",
        "1.0.29-3build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "tightvncserver",
            "binary_version": "1.3.10-0ubuntu4"
          },
          {
            "binary_name": "xtightvncviewer",
            "binary_version": "1.3.10-0ubuntu4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "tightvnc",
        "purl": "pkg:deb/ubuntu/tightvnc@1.3.10-0ubuntu4?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.3.10-0ubuntu3",
        "1.3.10-0ubuntu4"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "tightvncserver",
            "binary_version": "1.3.10-0ubuntu5"
          },
          {
            "binary_name": "xtightvncviewer",
            "binary_version": "1.3.10-0ubuntu5"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "tightvnc",
        "purl": "pkg:deb/ubuntu/tightvnc@1.3.10-0ubuntu5?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
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          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.3.10-0ubuntu5"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "tightvncpasswd",
            "binary_version": "1:1.3.10-5"
          },
          {
            "binary_name": "tightvncserver",
            "binary_version": "1:1.3.10-5"
          },
          {
            "binary_name": "xtightvncviewer",
            "binary_version": "1:1.3.10-5"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "tightvnc",
        "purl": "pkg:deb/ubuntu/tightvnc@1:1.3.10-5?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
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      "versions": [
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        "1:1.3.10-5"
      ]
    },
    {
      "ecosystem_specific": {
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            "binary_version": "1:1.3.10-8"
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          {
            "binary_name": "tightvncserver",
            "binary_version": "1:1.3.10-8"
          },
          {
            "binary_name": "xtightvncviewer",
            "binary_version": "1:1.3.10-8"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "tightvnc",
        "purl": "pkg:deb/ubuntu/tightvnc@1:1.3.10-8?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
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            {
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            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:1.3.10-7",
        "1:1.3.10-7build1",
        "1:1.3.10-7build2",
        "1:1.3.10-8"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "tightvncpasswd",
            "binary_version": "1:1.3.10-10"
          },
          {
            "binary_name": "tightvncserver",
            "binary_version": "1:1.3.10-10"
          },
          {
            "binary_name": "xtightvncviewer",
            "binary_version": "1:1.3.10-10"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "tightvnc",
        "purl": "pkg:deb/ubuntu/tightvnc@1:1.3.10-10?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:1.3.10-9",
        "1:1.3.10-10"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "tightvncpasswd",
            "binary_version": "1:1.3.10-10build1"
          },
          {
            "binary_name": "tightvncserver",
            "binary_version": "1:1.3.10-10build1"
          },
          {
            "binary_name": "xtightvncviewer",
            "binary_version": "1:1.3.10-10build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "tightvnc",
        "purl": "pkg:deb/ubuntu/tightvnc@1:1.3.10-10build1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:1.3.10-10",
        "1:1.3.10-10build1"
      ]
    }
  ],
  "aliases": [],
  "details": "LibVNC before commit c3115350eb8bb635d0fdb4dbbb0d0541f38ed19c contains a CWE-835: Infinite loop vulnerability in VNC client code. Vulnerability allows attacker to consume excessive amount of resources like CPU and RAM",
  "id": "UBUNTU-CVE-2018-20021",
  "modified": "2026-05-20T14:50:57Z",
  "published": "2018-12-19T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2018-20021"
    },
    {
      "type": "REPORT",
      "url": "https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-031-libvnc-infinite-loop/"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-3877-1"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-4547-1"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-4547-2"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-4587-1"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2018-20021"
    }
  ],
  "related": [
    "USN-3877-1",
    "USN-4547-1",
    "USN-4547-2",
    "USN-4587-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2018-20021"
  ]
}



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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.


Detection rules are retrieved from Rulezet.