{"id":"UBUNTU-CVE-2019-20840","details":"An issue was discovered in LibVNCServer before 0.9.13. libvncserver/ws_decode.c can lead to a crash because of unaligned accesses in hybiReadAndDecode.","modified":"2026-04-27T16:06:42.000581Z","published":"2020-06-17T16:15:00Z","related":["USN-4434-1"],"upstream":["CVE-2019-20840"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2019-20840"},{"type":"REPORT","url":"https://github.com/LibVNC/libvncserver/compare/LibVNCServer-0.9.12...LibVNCServer-0.9.13"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-4434-1"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2019-20840"}],"affected":[{"package":{"name":"x11vnc","ecosystem":"Ubuntu:14.04:LTS","purl":"pkg:deb/ubuntu/x11vnc@0.9.13-1.1?arch=source&distro=trusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.9.13-1.1"],"ecosystem_specific":{"binaries":[{"binary_name":"x11vnc","binary_version":"0.9.13-1.1"},{"binary_name":"x11vnc-data","binary_version":"0.9.13-1.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2019/UBUNTU-CVE-2019-20840.json"}},{"package":{"name":"libvncserver","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/libvncserver@0.9.10+dfsg-3ubuntu0.16.04.5?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.9.10+dfsg-3ubuntu0.16.04.5"}]}],"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","0.9.10+dfsg-3ubuntu0.16.04.3","0.9.10+dfsg-3ubuntu0.16.04.4"],"ecosystem_specific":{"binaries":[{"binary_name":"libvncclient1","binary_version":"0.9.10+dfsg-3ubuntu0.16.04.5"},{"binary_name":"libvncserver-config","binary_version":"0.9.10+dfsg-3ubuntu0.16.04.5"},{"binary_name":"libvncserver1","binary_version":"0.9.10+dfsg-3ubuntu0.16.04.5"}],"availability":"No 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