CVE-2018-20020

Publication date 19 December 2018

Last updated 11 July 2025

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

9.8 · Critical

Score breakdown

Description

LibVNC before commit 7b1ef0ffc4815cab9a96c7278394152bdc89dc4d contains heap out-of-bound write vulnerability inside structure in VNC client code that can result remote code execution

Status

Package Ubuntu Release Status
tightvnc 25.10 questing
Needs evaluation
25.04 plucky
Needs evaluation
24.10 oracular Ignored end of life, was needs-triage
24.04 LTS noble
Needs evaluation
23.10 mantic Ignored end of life, was needs-triage
23.04 lunar Ignored end of life, was needs-triage
22.10 kinetic Ignored end of life, was needs-triage
22.04 LTS jammy
Needs evaluation
21.10 impish Ignored end of life
21.04 hirsute Ignored end of life
20.10 groovy Ignored end of life
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
14.04 LTS trusty
Fixed 1.3.9-6.5+deb8u1build0.14.04.1~esm1
libvncserver 25.10 questing
Not affected
25.04 plucky
Not affected
24.10 oracular
Not affected
24.04 LTS noble
Not affected
23.10 mantic
Not affected
23.04 lunar
Not affected
22.10 kinetic
Not affected
22.04 LTS jammy
Not affected
21.10 impish
Not affected
21.04 hirsute
Not affected
20.10 groovy
Not affected
20.04 LTS focal
Not affected
19.04 disco
Not affected
18.10 cosmic
Fixed 0.9.11+dfsg-1.1ubuntu0.1
18.04 LTS bionic
Fixed 0.9.11+dfsg-1ubuntu1.1
16.04 LTS xenial
Fixed 0.9.10+dfsg-3ubuntu0.16.04.3
14.04 LTS trusty
Fixed 0.9.9+dfsg-1ubuntu1.4
x11vnc 25.10 questing
Not affected
25.04 plucky
Not affected
24.10 oracular
Not affected
24.04 LTS noble
Not affected
23.10 mantic
Not affected
23.04 lunar
Not affected
22.10 kinetic
Not affected
22.04 LTS jammy
Not affected
21.10 impish
Not affected
21.04 hirsute
Not affected
20.10 groovy
Not affected
20.04 LTS focal
Not affected
19.04 disco
Not affected
18.10 cosmic Ignored end of life
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
italc 25.10 questing Not in release
25.04 plucky Not in release
24.10 oracular Not in release
24.04 LTS noble Not in release
23.10 mantic Not in release
23.04 lunar Not in release
22.10 kinetic Not in release
22.04 LTS jammy Not in release
21.10 impish Not in release
21.04 hirsute Not in release
20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Fixed 1:3.0.3+dfsg1-3ubuntu0.1
16.04 LTS xenial
Fixed 1:2.0.2+dfsg1-4ubuntu0.1
14.04 LTS trusty Not in release
ssvnc 25.10 questing
Not affected
25.04 plucky
Not affected
24.10 oracular
Not affected
24.04 LTS noble
Not affected
23.10 mantic
Not affected
23.04 lunar
Not affected
22.10 kinetic
Not affected
22.04 LTS jammy
Not affected
21.10 impish
Not affected
21.04 hirsute
Not affected
20.10 groovy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic
Vulnerable
16.04 LTS xenial
Fixed 1.0.29-2+deb8u1build0.16.04.1
14.04 LTS trusty Not in release

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Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
libvncserver

Severity score breakdown

Parameter Value
Base score 9.8 · Critical
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Related Ubuntu Security Notices (USN)

    • USN-3877-1
    • LibVNCServer vulnerabilities
    • 31 January 2019
    • USN-4547-1
    • iTALC vulnerabilities
    • 28 September 2020
    • USN-4547-2
    • SSVNC vulnerabilities
    • 28 September 2020
    • USN-4587-1
    • iTALC vulnerabilities
    • 20 October 2020

Other references