CVE-2017-18922: Canonical Ubuntu Linux

Critical severity, CVSS 9.8. EPSS: 2.3% chance of exploitation in the next 30 days.

It was discovered that websockets.c in LibVNCServer prior to 0.9.12 did not properly decode certain WebSocket frames. A malicious attacker could exploit this by sending specially crafted WebSocket frames to a server, causing a heap-based buffer overflow.

Affected products

• Canonical Ubuntu Linux: version 16.04 only; version 18.04 only; version 19.10 only; version 20.04 only
• Fedoraproject Fedora: version 31 only; version 32 only
• Libvncserver Project Libvncserver: before 0.9.12 (fixed in 0.9.12)
• Opensuse Leap: version 15.1 only; version 15.2 only
• Siemens SIMATIC ITC1500 Firmware: from 3.0.0.0, before 3.2.1.0 (fixed in 3.2.1.0)
• Siemens SIMATIC ITC1500 Pro Firmware: from 3.0.0.0, before 3.2.1.0 (fixed in 3.2.1.0)
• Siemens SIMATIC ITC1900 Firmware: from 3.0.0.0, before 3.2.1.0 (fixed in 3.2.1.0)
• Siemens SIMATIC ITC1900 Pro Firmware: from 3.0.0.0, before 3.2.1.0 (fixed in 3.2.1.0)
• Siemens SIMATIC ITC2200 Firmware: from 3.0.0.0, before 3.2.1.0 (fixed in 3.2.1.0)
• Siemens SIMATIC ITC2200 Pro Firmware: from 3.0.0.0, before 3.2.1.0 (fixed in 3.2.1.0)

Published 2020-06-30. Last modified 2026-06-17.