{"id":"UBUNTU-CVE-2018-20021","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","modified":"2026-01-30T01:40:46.651461Z","published":"2018-12-19T00:00:00Z","related":["USN-3877-1","USN-4547-1","USN-4547-2","USN-4587-1"],"upstream":["CVE-2018-20021"],"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"}],"affected":[{"package":{"name":"libvncserver","ecosystem":"Ubuntu:14.04:LTS","purl":"pkg:deb/ubuntu/libvncserver@0.9.9+dfsg-1ubuntu1.4?arch=source&distro=trusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.9.9+dfsg-1ubuntu1.4"}]}],"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":"No subscription required","binaries":[{"binary_version":"0.9.9+dfsg-1ubuntu1.4","binary_name":"libvncserver-config"},{"binary_version":"0.9.9+dfsg-1ubuntu1.4","binary_name":"libvncserver-dev"},{"binary_version":"0.9.9+dfsg-1ubuntu1.4","binary_name":"libvncserver0"},{"binary_version":"0.9.9+dfsg-1ubuntu1.4","binary_name":"linuxvnc"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2018/UBUNTU-CVE-2018-20021.json"}},{"package":{"name":"tightvnc","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/tightvnc@1.3.9-6.5+deb8u1build0.14.04.1~esm1?arch=source&distro=trusty/esm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.3.9-6.5+deb8u1build0.14.04.1~esm1"}]}],"versions":["1.3.9-6.4","1.3.9-6.4ubuntu1"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro","binaries":[{"binary_version":"1.3.9-6.5+deb8u1build0.14.04.1~esm1","binary_name":"tightvncserver"},{"binary_version":"1.3.9-6.5+deb8u1build0.14.04.1~esm1","binary_name":"xtightvncviewer"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2018/UBUNTU-CVE-2018-20021.json"}},{"package":{"name":"italc","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/italc@1:2.0.2+dfsg1-4ubuntu0.1?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:2.0.2+dfsg1-4ubuntu0.1"}]}],"versions":["1:2.0.2+dfsg1-3","1:2.0.2+dfsg1-4"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_version":"1:2.0.2+dfsg1-4ubuntu0.1","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"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2018/UBUNTU-CVE-2018-20021.json"}},{"package":{"name":"libvncserver","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/libvncserver@0.9.10+dfsg-3ubuntu0.16.04.3?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.9.10+dfsg-3ubuntu0.16.04.3"}]}],"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_version":"0.9.10+dfsg-3ubuntu0.16.04.3","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":"libvncserver-dev"},{"binary_version":"0.9.10+dfsg-3ubuntu0.16.04.3","binary_name":"libvncserver1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2018/UBUNTU-CVE-2018-20021.json"}},{"package":{"name":"ssvnc","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/ssvnc@1.0.29-2+deb8u1build0.16.04.1?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.0.29-2+deb8u1build0.16.04.1"}]}],"versions":["1.0.29-2build1"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_version":"1.0.29-2+deb8u1build0.16.04.1","binary_name":"ssvnc"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2018/UBUNTU-CVE-2018-20021.json"}},{"package":{"name":"tightvnc","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/tightvnc@1.3.10-0ubuntu3?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.10-0ubuntu2","1.3.10-0ubuntu3"],"ecosystem_specific":{"binaries":[{"binary_version":"1.3.10-0ubuntu3","binary_name":"tightvncserver"},{"binary_version":"1.3.10-0ubuntu3","binary_name":"xtightvncviewer"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2018/UBUNTU-CVE-2018-20021.json"}},{"package":{"name":"italc","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/italc@1:3.0.3+dfsg1-3ubuntu0.1?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:3.0.3+dfsg1-3ubuntu0.1"}]}],"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_version":"1:3.0.3+dfsg1-3ubuntu0.1","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"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2018/UBUNTU-CVE-2018-20021.json"}},{"package":{"name":"libvncserver","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/libvncserver@0.9.11+dfsg-1ubuntu1.1?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.9.11+dfsg-1ubuntu1.1"}]}],"versions":["0.9.11+dfsg-1","0.9.11+dfsg-1ubuntu1"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_version":"0.9.11+dfsg-1ubuntu1.1","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":"libvncserver-dev"},{"binary_version":"0.9.11+dfsg-1ubuntu1.1","binary_name":"libvncserver1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2018/UBUNTU-CVE-2018-20021.json"}},{"package":{"name":"ssvnc","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/ssvnc@1.0.29-3build1?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0.29-3","1.0.29-3build1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.0.29-3build1","binary_name":"ssvnc"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2018/UBUNTU-CVE-2018-20021.json"}},{"package":{"name":"tightvnc","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/tightvnc@1.3.10-0ubuntu4?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.10-0ubuntu3","1.3.10-0ubuntu4"],"ecosystem_specific":{"binaries":[{"binary_version":"1.3.10-0ubuntu4","binary_name":"tightvncserver"},{"binary_version":"1.3.10-0ubuntu4","binary_name":"xtightvncviewer"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2018/UBUNTU-CVE-2018-20021.json"}},{"package":{"name":"tightvnc","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/tightvnc@1.3.10-0ubuntu5?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.10-0ubuntu5"],"ecosystem_specific":{"binaries":[{"binary_version":"1.3.10-0ubuntu5","binary_name":"tightvncserver"},{"binary_version":"1.3.10-0ubuntu5","binary_name":"xtightvncviewer"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2018/UBUNTU-CVE-2018-20021.json"}},{"package":{"name":"tightvnc","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/tightvnc@1:1.3.10-5?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:1.3.10-3","1:1.3.10-5"],"ecosystem_specific":{"binaries":[{"binary_version":"1:1.3.10-5","binary_name":"tightvncpasswd"},{"binary_version":"1:1.3.10-5","binary_name":"tightvncserver"},{"binary_version":"1:1.3.10-5","binary_name":"xtightvncviewer"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2018/UBUNTU-CVE-2018-20021.json"}},{"package":{"name":"tightvnc","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/tightvnc@1:1.3.10-8?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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_version":"1:1.3.10-8","binary_name":"tightvncpasswd"},{"binary_version":"1:1.3.10-8","binary_name":"tightvncserver"},{"binary_version":"1:1.3.10-8","binary_name":"xtightvncviewer"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2018/UBUNTU-CVE-2018-20021.json"}},{"package":{"name":"tightvnc","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/tightvnc@1:1.3.10-10?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:1.3.10-9","1:1.3.10-10"],"ecosystem_specific":{"binaries":[{"binary_version":"1:1.3.10-10","binary_name":"tightvncpasswd"},{"binary_version":"1:1.3.10-10","binary_name":"tightvncserver"},{"binary_version":"1:1.3.10-10","binary_name":"xtightvncviewer"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2018/UBUNTU-CVE-2018-20021.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}