CVE catalog

CVE-2018-20023

libvncserver: CVE-2018-20023

Severity: Medium · CVSS 4.3CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
Published: Dec 19, 2018, 12:00:00 AM UTC
Source: [NVD] · [CVE record]
EPSS: 2.50% · Oct 25, 2026

LibVNC before 8b06f835e259652b0ff026898014fc7297ade858 contains CWE-665: Improper Initialization vulnerability in VNC Repeater 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

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	veyon	sid	`4.9.7+repack1-1.1`	fixed
Debian	veyon	trixie	`4.9.5+repack1-2`	fixed
Debian	veyon	bookworm	`4.7.5+repack1-1`	fixed
Debian	libvncserver	sid	`0.9.15+dfsg-6`	fixed
Debian	libvncserver	forky	`0.9.15+dfsg-6`	fixed
Debian	libvncserver	trixie	`0.9.15+dfsg-1+deb13u2`	fixed
Debian	libvncserver	bookworm	`0.9.14+dfsg-1+deb12u2`	fixed
Ubuntu	libvncserver	14.04	`0.9.9+dfsg-1`	vulnerable
Ubuntu	libvncserver	14.04	`0.9.9+dfsg-1ubuntu1`	vulnerable
Ubuntu	libvncserver	14.04	`0.9.9+dfsg-1ubuntu1.1`	vulnerable
Ubuntu	libvncserver	14.04	`0.9.9+dfsg-1ubuntu1.2`	vulnerable
Ubuntu	libvncserver	14.04	`0.9.9+dfsg-1ubuntu1.3`	vulnerable
Ubuntu	libvncserver	14.04	`0.9.9+dfsg-1ubuntu1.4`	fixed
Ubuntu	italc	16.04	`1:2.0.2+dfsg1-3`	vulnerable
Ubuntu	italc	16.04	`1:2.0.2+dfsg1-4`	vulnerable
Ubuntu	italc	16.04	`1:2.0.2+dfsg1-4ubuntu0.1`	fixed
Ubuntu	libvncserver	16.04	`0.9.10+dfsg-3`	vulnerable
Ubuntu	libvncserver	16.04	`0.9.10+dfsg-3build1`	vulnerable
Ubuntu	libvncserver	16.04	`0.9.10+dfsg-3ubuntu0.16.04.1`	vulnerable
Ubuntu	libvncserver	16.04	`0.9.10+dfsg-3ubuntu0.16.04.2`	vulnerable
Ubuntu	libvncserver	16.04	`0.9.10+dfsg-3ubuntu0.16.04.3`	fixed
Ubuntu	italc	18.04	`1:3.0.3+dfsg1-1`	vulnerable
Ubuntu	italc	18.04	`1:3.0.3+dfsg1-2`	vulnerable
Ubuntu	italc	18.04	`1:3.0.3+dfsg1-2build1`	vulnerable
Ubuntu	italc	18.04	`1:3.0.3+dfsg1-2ubuntu1`	vulnerable
Ubuntu	italc	18.04	`1:3.0.3+dfsg1-3`	vulnerable
Ubuntu	italc	18.04	`1:3.0.3+dfsg1-3ubuntu0.1`	fixed
Ubuntu	libvncserver	18.04	`0.9.11+dfsg-1`	vulnerable
Ubuntu	libvncserver	18.04	`0.9.11+dfsg-1ubuntu1`	vulnerable
Ubuntu	libvncserver	18.04	`0.9.11+dfsg-1ubuntu1.1`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	veyon	source	sid	`4.1.4+repack1-1`	not yet assigned	Not reported	Not reported
Debian	veyon	source	trixie	`4.1.4+repack1-1`	not yet assigned	Not reported	Not reported
Debian	veyon	source	bookworm	`4.1.4+repack1-1`	not yet assigned	Not reported	Not reported
Debian	libvncserver	source	sid	`0.9.11+dfsg-1.2`	not yet assigned	Not reported	[916941]
Debian	libvncserver	source	forky	`0.9.11+dfsg-1.2`	not yet assigned	Not reported	[916941]
Debian	libvncserver	source	trixie	`0.9.11+dfsg-1.2`	not yet assigned	Not reported	[916941]
Debian	libvncserver	source	bookworm	`0.9.11+dfsg-1.2`	not yet assigned	Not reported	[916941]
Ubuntu	libvncserver	deb	14.04	`0.9.9+dfsg-1ubuntu1.4`	Not reported	UBUNTU-CVE-2018-20023	Not reported
Ubuntu	italc	deb	16.04	`1:2.0.2+dfsg1-4ubuntu0.1`	Not reported	UBUNTU-CVE-2018-20023	Not reported
Ubuntu	libvncserver	deb	16.04	`0.9.10+dfsg-3ubuntu0.16.04.3`	Not reported	UBUNTU-CVE-2018-20023	Not reported
Ubuntu	italc	deb	18.04	`1:3.0.3+dfsg1-3ubuntu0.1`	Not reported	UBUNTU-CVE-2018-20023	Not reported
Ubuntu	libvncserver	deb	18.04	`0.9.11+dfsg-1ubuntu1.1`	Not reported	UBUNTU-CVE-2018-20023	Not reported

[Debian bug #916941]

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[libveyon-core]Fixed
Source package: [veyon]
Details (2)
- 4.7.5+repack1-1 · amd64 · bookworm
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · bookworm; dsa · veyon · debian · 12
- 4.7.5+repack1-1 · arm64 · bookworm
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · bookworm; dsa · veyon · debian · 12
[libvncclient1]Fixed
Source package: [libvncserver]
Details (2)
- 0.9.14+dfsg-1+deb12u2 · amd64 · bookworm
  Fixed · Fixed: 0.9.11+dfsg-1.2
  dsa · libvncserver · debian · bookworm; dsa · libvncserver · debian · 12
- 0.9.14+dfsg-1+deb12u2 · arm64 · bookworm
  Fixed · Fixed: 0.9.11+dfsg-1.2
  dsa · libvncserver · debian · bookworm; dsa · libvncserver · debian · 12
[libvncserver1]Fixed
Source package: [libvncserver]
Details (2)
- 0.9.14+dfsg-1+deb12u2 · amd64 · bookworm
  Fixed · Fixed: 0.9.11+dfsg-1.2
  dsa · libvncserver · debian · bookworm; dsa · libvncserver · debian · 12
- 0.9.14+dfsg-1+deb12u2 · arm64 · bookworm
  Fixed · Fixed: 0.9.11+dfsg-1.2
  dsa · libvncserver · debian · bookworm; dsa · libvncserver · debian · 12
[libvncserver-dev]Fixed
Source package: [libvncserver]
Details (2)
- 0.9.14+dfsg-1+deb12u2 · amd64 · bookworm
  Fixed · Fixed: 0.9.11+dfsg-1.2
  dsa · libvncserver · debian · bookworm; dsa · libvncserver · debian · 12
- 0.9.14+dfsg-1+deb12u2 · arm64 · bookworm
  Fixed · Fixed: 0.9.11+dfsg-1.2
  dsa · libvncserver · debian · bookworm; dsa · libvncserver · debian · 12
[veyon-configurator]Fixed
Source package: [veyon]
Details (2)
- 4.7.5+repack1-1 · amd64 · bookworm
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · bookworm; dsa · veyon · debian · 12
- 4.7.5+repack1-1 · arm64 · bookworm
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · bookworm; dsa · veyon · debian · 12
[veyon-master]Fixed
Source package: [veyon]
Details (2)
- 4.7.5+repack1-1 · amd64 · bookworm
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · bookworm; dsa · veyon · debian · 12
- 4.7.5+repack1-1 · arm64 · bookworm
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · bookworm; dsa · veyon · debian · 12
[veyon-plugins]Fixed
Source package: [veyon]
Details (2)
- 4.7.5+repack1-1 · amd64 · bookworm
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · bookworm; dsa · veyon · debian · 12
- 4.7.5+repack1-1 · arm64 · bookworm
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · bookworm; dsa · veyon · debian · 12
[veyon-service]Fixed
Source package: [veyon]
Details (2)
- 4.7.5+repack1-1 · amd64 · bookworm
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · bookworm; dsa · veyon · debian · 12
- 4.7.5+repack1-1 · arm64 · bookworm
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · bookworm; dsa · veyon · debian · 12

[Debian 13 (Trixie)]

[libveyon-core]Fixed
Source package: [veyon]
Details (2)
- 4.9.5+repack1-2 · amd64 · trixie
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · 13
- 4.9.5+repack1-2 · arm64 · trixie
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · 13
[libvncclient1]Fixed
Source package: [libvncserver]
Details (2)
- 0.9.15+dfsg-1+deb13u2 · amd64 · trixie
  Fixed · Fixed: 0.9.11+dfsg-1.2
  dsa · libvncserver · debian · 13
- 0.9.15+dfsg-1+deb13u2 · arm64 · trixie
  Fixed · Fixed: 0.9.11+dfsg-1.2
  dsa · libvncserver · debian · 13
[libvncserver1]Fixed
Source package: [libvncserver]
Details (2)
- 0.9.15+dfsg-1+deb13u2 · amd64 · trixie
  Fixed · Fixed: 0.9.11+dfsg-1.2
  dsa · libvncserver · debian · 13
- 0.9.15+dfsg-1+deb13u2 · arm64 · trixie
  Fixed · Fixed: 0.9.11+dfsg-1.2
  dsa · libvncserver · debian · 13
[libvncserver-dev]Fixed
Source package: [libvncserver]
Details (2)
- 0.9.15+dfsg-1+deb13u2 · amd64 · trixie
  Fixed · Fixed: 0.9.11+dfsg-1.2
  dsa · libvncserver · debian · 13
- 0.9.15+dfsg-1+deb13u2 · arm64 · trixie
  Fixed · Fixed: 0.9.11+dfsg-1.2
  dsa · libvncserver · debian · 13
[veyon-configurator]Fixed
Source package: [veyon]
Details (2)
- 4.9.5+repack1-2 · amd64 · trixie
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · 13
- 4.9.5+repack1-2 · arm64 · trixie
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · 13
[veyon-master]Fixed
Source package: [veyon]
Details (2)
- 4.9.5+repack1-2 · amd64 · trixie
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · 13
- 4.9.5+repack1-2 · arm64 · trixie
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · 13
[veyon-plugins]Fixed
Source package: [veyon]
Details (2)
- 4.9.5+repack1-2 · amd64 · trixie
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · 13
- 4.9.5+repack1-2 · arm64 · trixie
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · 13
[veyon-service]Fixed
Source package: [veyon]
Details (2)
- 4.9.5+repack1-2 · amd64 · trixie
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · 13
- 4.9.5+repack1-2 · arm64 · trixie
  Fixed · Fixed: 4.1.4+repack1-1
  dsa · veyon · debian · 13

Observed: Oct 23, 2026, 5:35:55 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database] · [SUSE security advisories and VEX]