CVE-2018-20022

Severity: high (CVSS 7.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-12-19 · updated 2026-06-17
Weakness: CWE-665

Description

LibVNC before 2f5b2ad1c6c99b1ac6482c95844a84d66bb52838 contains multiple weaknesses CWE-665: Improper Initialization vulnerability in VNC client code that allows attacker to read stack memory and can be abuse for information disclosure. Combined with another vulnerability, it can be used to leak stack memory layout and in bypassing ASLR

Affected products

Canonical Ubuntu Linux: 14.04, 16.04, 18.04, 18.10
Debian Linux: 8.0, 9.0
Libvnc Project Libvncserver: before 0.9.12 — fixed in 0.9.12

How to fix

Upgrade to a fixed version: Libvnc Project Libvncserver 0.9.12. Check the vendor advisory for mitigations.

References

https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-032-libvnc-multiple-memory-leaks/
https://lists.debian.org/debian-lts-announce/2018/12/msg00017.html
https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
https://lists.debian.org/debian-lts-announce/2019/11/msg00033.html
https://lists.debian.org/debian-lts-announce/2019/12/msg00028.html
https://security.gentoo.org/glsa/201908-05
https://security.gentoo.org/glsa/202006-06
https://usn.ubuntu.com/3877-1/
https://usn.ubuntu.com/4547-1/
https://usn.ubuntu.com/4547-2/
https://usn.ubuntu.com/4587-1/
https://www.debian.org/security/2019/dsa-4383

Get alerted when CVE-2018-20022 or the next vulnerability affects your stack