HOMEVULNERABILITIESCVE-2018-20019
CRITICAL

CVE-2018-20019

CWE-787Published: December 19, 2018· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official Description

LibVNC before commit a83439b9fbe0f03c48eb94ed05729cb016f8b72f contains multiple heap out-of-bound write vulnerabilities in VNC client code that can result remote code execution

NVD Source

Technical Analysis

CVE-2018-20019 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

From a weakness classification perspective (CWE-787): Out-of-bounds write vulnerabilities can lead to data corruption, crashes, or arbitrary code execution.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

Canonical1 product(s)
ubuntu linux
Debian1 product(s)
debian linux
libvnc_project1 product(s)
libvncserver
siemens12 product(s)
simatic itc1500 firmwaresimatic itc1500simatic itc1500 pro firmwaresimatic itc1500 prosimatic itc1900 firmwaresimatic itc1900simatic itc1900 pro firmwaresimatic itc1900 prosimatic itc2200 firmwaresimatic itc2200simatic itc2200 pro firmwaresimatic itc2200 pro
Source: NVD CPE · 19 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdf
PATCHhttps://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdf
ADVISORYhttps://lists.debian.org/debian-lts-announce/2018/12/msg00017.html
ADVISORYhttps://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
ADVISORYhttps://security.gentoo.org/glsa/201908-05
ADVISORYhttps://usn.ubuntu.com/3877-1/
ADVISORYhttps://usn.ubuntu.com/4547-1/
ADVISORYhttps://usn.ubuntu.com/4587-1/
ADVISORYhttps://www.debian.org/security/2019/dsa-4383
ADVISORYhttps://lists.debian.org/debian-lts-announce/2018/12/msg00017.html
ADVISORYhttps://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
ADVISORYhttps://security.gentoo.org/glsa/201908-05
ADVISORYhttps://usn.ubuntu.com/3877-1/
ADVISORYhttps://usn.ubuntu.com/4547-1/
ADVISORYhttps://usn.ubuntu.com/4587-1/
ADVISORYhttps://www.debian.org/security/2019/dsa-4383

All References (18)

→
https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdfPatch · Third Party Advisory
→
https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-029-libvnc-multiple-heap-out-of-bound-vulnerabilities/Broken Link
→
https://lists.debian.org/debian-lts-announce/2018/12/msg00017.htmlMailing List · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2019/10/msg00042.htmlMailing List · Third Party Advisory
→
https://security.gentoo.org/glsa/201908-05Third Party Advisory
→
https://usn.ubuntu.com/3877-1/Third Party Advisory
→
https://usn.ubuntu.com/4547-1/Third Party Advisory
→
https://usn.ubuntu.com/4587-1/Third Party Advisory
→
https://www.debian.org/security/2019/dsa-4383Third Party Advisory
→
https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdfPatch · Third Party Advisory
→
https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-029-libvnc-multiple-heap-out-of-bound-vulnerabilities/Broken Link
→
https://lists.debian.org/debian-lts-announce/2018/12/msg00017.htmlMailing List · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2019/10/msg00042.htmlMailing List · Third Party Advisory
→
https://security.gentoo.org/glsa/201908-05Third Party Advisory
→
https://usn.ubuntu.com/3877-1/Third Party Advisory

Quick Facts

CVE IDCVE-2018-20019
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-787
CISA KEVNo
Affected4 vendor(s)
PublishedDec 19, 2018

Related CVEs (CWE-787)

CVE-2015-5098
10.0
CVE-2015-5096
10.0
CVE-2015-5105
10.0
CVE-2013-5610
10.0
CVE-2004-0978
10.0
CVE-2018-6692
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2018-20019 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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