Infinite loop in LibVNCServer - CVE-2018-20021

Vulnerability identifier: #VU17127

CSH Severity: Low

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2018-20021

CWE-ID: CWE-835

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to infinite loop in VNC client code. A remote attacker can consume excessive amount of resources like CPU and RAM and perform a denial of service (DoS) attack.

LibVNCServer
Gentoo Linux
Opensuse
Ubuntu
libvncserver (Debian package)
italc-client (Ubuntu package)
italc-master (Ubuntu package)
libitalccore (Ubuntu package)

Update to version 0.9.12.

LibVNCServer - update to 0.9.12
libvncserver (Debian package) - addressed in versions 0.9.9+dfsg2-6.1+deb8u5, 0.9.11+dfsg-1.3~deb9u1
italc-client (Ubuntu package) - update to 1:3.0.3+dfsg1-3ubuntu0.1
italc-master (Ubuntu package) - update to 1:3.0.3+dfsg1-3ubuntu0.1
libitalccore (Ubuntu package) - update to 1:3.0.3+dfsg1-3ubuntu0.1

• https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-031-libvnc-infinite-loop/

• Multiple vulnerabilities in LibVNCServer
• OpenSUSE Linux update for LibVNCServer
• Debian update for libvncserver
• Gentoo update for ssvnc
• Ubuntu update for italc