HOMEVULNERABILITIESCVE-2018-20023
HIGH

CVE-2018-20023

CWE-665Published: December 19, 2018· Updated: Jun 17, 2026

7.5
CVSS v3.1

Official Description

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

NVD Source

Technical Analysis

CVE-2018-20023 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), with a CVSS base score of 7.5.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityNone
AvailabilityNone
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected Vendors & Products

Canonical1 product(s)
ubuntu linux
Debian1 product(s)
debian linux
libvnc_project1 product(s)
libvncserver
Source: NVD CPE · 7 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

ADVISORYhttps://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-033-libvnc-memory-leak/
ADVISORYhttps://lists.debian.org/debian-lts-announce/2018/12/msg00017.html
ADVISORYhttps://usn.ubuntu.com/3877-1/
ADVISORYhttps://www.debian.org/security/2019/dsa-4383
ADVISORYhttps://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-033-libvnc-memory-leak/
ADVISORYhttps://lists.debian.org/debian-lts-announce/2018/12/msg00017.html
ADVISORYhttps://usn.ubuntu.com/3877-1/
ADVISORYhttps://www.debian.org/security/2019/dsa-4383

All References (16)

→
https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-033-libvnc-memory-leak/Third Party Advisory
→
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.html
→
https://security.gentoo.org/glsa/201908-05
→
https://usn.ubuntu.com/3877-1/Third Party Advisory
→
https://usn.ubuntu.com/4547-1/
→
https://usn.ubuntu.com/4587-1/
→
https://www.debian.org/security/2019/dsa-4383Third Party Advisory
→
https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-033-libvnc-memory-leak/Third Party Advisory
→
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.html
→
https://security.gentoo.org/glsa/201908-05
→
https://usn.ubuntu.com/3877-1/Third Party Advisory
→
https://usn.ubuntu.com/4547-1/
→
https://usn.ubuntu.com/4587-1/

Quick Facts

CVE IDCVE-2018-20023
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-665
CISA KEVNo
Affected3 vendor(s)
PublishedDec 19, 2018

Related CVEs (CWE-665)

CVE-2023-20591
10.0
CVE-2022-0947
9.8
CVE-2015-8367
9.8
CVE-2022-37128
9.8
CVE-2022-21724
9.8
CVE-2019-3464
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2018-20023 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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