Integer overflow in LibVNCServer - CVE-2019-20788

Vulnerability identifier: #VU29385

CSH Severity: Medium

CVSS v4: 7.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2019-20788

CWE-ID: CWE-190

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to integer overflow in libvncclient/cursor.c  when processing large height or width values. A remote attacker can trick the victim to connect to a malicious VNC server, trigger integer overflow and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

LibVNCServer
Opensuse
Ubuntu
SIMATIC ITC2200 PRO
SIMATIC ITC2200
SIMATIC ITC1900 PRO
SIMATIC ITC1900
SIMATIC ITC1500 PRO
SIMATIC ITC1500
libvncclient1 (Ubuntu package)
libvncserver1 (Ubuntu package)

Install updates from vendor's website.

LibVNCServer - update to 0.9.13
SIMATIC ITC2200 PRO - update to
libvncclient1 (Ubuntu package) - addressed in versions 0.9.10+dfsg-3ubuntu0.16.04.4, 0.9.11+dfsg-1.3ubuntu0.1, 0.9.11+dfsg-1ubuntu1.2, 0.9.12+dfsg-9ubuntu0.1
libvncserver1 (Ubuntu package) - addressed in versions 0.9.10+dfsg-3ubuntu0.16.04.4, 0.9.11+dfsg-1.3ubuntu0.1, 0.9.11+dfsg-1ubuntu1.2, 0.9.12+dfsg-9ubuntu0.1
SIMATIC ITC2200 PRO - update to 3.2.1.0
SIMATIC ITC2200 - update to 3.2.1.0
SIMATIC ITC1900 PRO - update to 3.2.1.0
SIMATIC ITC1900 - update to 3.2.1.0
SIMATIC ITC1500 PRO - update to 3.2.1.0
SIMATIC ITC1500 - update to 3.2.1.0

• http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00027.html
• https://github.com/LibVNC/libvncserver/commit/54220248886b5001fbbb9fa73c4e1a2cb9413fed

• Multiple vulnerabilities in LibVNCServer
• OpenSUSE Linux update for LibVNCServer
• Multiple vulnerabilities in Siemens SIMATIC ITC
• Ubuntu update for libvncserver