CVE-2018-20750: Canonical Ubuntu Linux

Critical severity, CVSS 9.8. EPSS: 3.3% chance of exploitation in the next 30 days.

LibVNC through 0.9.12 contains a heap out-of-bounds write vulnerability in libvncserver/rfbserver.c. The fix for CVE-2018-15127 was incomplete.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 18.04 only; version 18.10 only
• Debian Debian Linux: version 8.0 only; version 9.0 only
• Libvnc Project Libvncserver: before 0.9.12 (fixed in 0.9.12)
• 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 2019-01-30. Last modified 2026-06-17.