The rfbProcessClientNormalMessage function in libvncserver/rfbserver.c in LibVNCServer 0.9.9 and earlier does not properly handle attempts to send a large amount of ClientCutText data, which allows remote attackers to cause a denial of service (memory consumption or daemon crash) via a crafted message that is processed by using a single unchecked malloc.
https://usn.ubuntu.com/4587-1/
https://usn.ubuntu.com/4573-1/
https://security.gentoo.org/glsa/201507-07
https://lists.debian.org/debian-lts-announce/2019/12/msg00028.html
https://lists.debian.org/debian-lts-announce/2019/11/msg00032.html
https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
https://github.com/newsoft/libvncserver/commit/6037a9074d52b1963c97cb28ea1096c7c14cbf28
http://www.openwall.com/lists/oss-security/2014/09/25/11
http://www.ocert.org/advisories/ocert-2014-007.html
http://www.debian.org/security/2014/dsa-3081
http://ubuntu.com/usn/usn-2365-1
http://secunia.com/advisories/61682
http://secunia.com/advisories/61506
http://seclists.org/oss-sec/2014/q3/639
http://lists.opensuse.org/opensuse-updates/2015-12/msg00022.html