Vulnerability Monitor

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CVE-2018-20023

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

Security Impact Summary

This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 7.5, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts confidentiality (data exposure), for affected systems. Impacting 3 products from libvnc_project, from debian, from canonical organizations running these solutions should prioritize assessment and patching.

Historical Context

First disclosed in 2018, this vulnerability was reported during a period defined by widespread IoT adoption challenges, mobile security concerns, and the emergence of advanced persistent threat (APT) techniques. Contemporary mitigation strategies focused on secure development practices and third-party component vetting.

Published

2018-12-19T16:29:00.513

Last Modified

2026-06-17T01:52:11.427

Status

Modified

Source

[email protected]

Severity

CVSSv3.0: 7.5 (HIGH)

CVSSv2 Vector

AV:N/AC:L/Au:N/C:P/I:N/A:N

Access Vector: NETWORK
Access Complexity: LOW
Authentication: NONE
Confidentiality Impact: PARTIAL
Integrity Impact: NONE
Availability Impact: NONE

Exploitability Score

10.0

Impact Score

2.9

Weaknesses

Type: Primary
CWE-665

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	libvnc_project	libvncserver	< 0.9.12	Yes
Operating System	debian	debian_linux	8.0	Yes
Operating System	debian	debian_linux	9.0	Yes
Operating System	canonical	ubuntu_linux	14.04	Yes
Operating System	canonical	ubuntu_linux	16.04	Yes
Operating System	canonical	ubuntu_linux	18.04	Yes
Operating System	canonical	ubuntu_linux	18.10	Yes

References

https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-033-libvnc-memory-leak/ Third Party Advisory ([email protected])
https://lists.debian.org/debian-lts-announce/2018/12/msg00017.html Mailing List, Third Party Advisory ([email protected])
https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html ([email protected])
https://security.gentoo.org/glsa/201908-05 ([email protected])
https://usn.ubuntu.com/3877-1/ Third Party Advisory ([email protected])
https://usn.ubuntu.com/4547-1/ ([email protected])
https://usn.ubuntu.com/4587-1/ ([email protected])
https://www.debian.org/security/2019/dsa-4383 Third Party Advisory ([email protected])
https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-033-libvnc-memory-leak/ Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://lists.debian.org/debian-lts-announce/2018/12/msg00017.html Mailing List, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html (af854a3a-2127-422b-91ae-364da2661108)
https://security.gentoo.org/glsa/201908-05 (af854a3a-2127-422b-91ae-364da2661108)
https://usn.ubuntu.com/3877-1/ Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://usn.ubuntu.com/4547-1/ (af854a3a-2127-422b-91ae-364da2661108)
https://usn.ubuntu.com/4587-1/ (af854a3a-2127-422b-91ae-364da2661108)
https://www.debian.org/security/2019/dsa-4383 Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For libvnc_project's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.