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Vulnerability record · CVE-2018-20020 · published 19 December 2018

CVE-2018-20020: Libvnc project libvncserver out-of-bounds write vulnerability

LLibvnc Project · Libvncserver

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

9.8 CVSS 3.0 Critical EPSS 8.6% · top 5.1% CWE-787 · Out-of-bounds write
9.8CVSS 3.0 base score, v2 7.5
8.6%EPSS exploitation probability, 30 days
NoNot in CISA KEV
3Affected product versions listed by NVD
22References
17 Jun 2026Last modified by NVD

Description

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

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

3 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-030-libvnc-heap-out-of-bound-write/ Third Party Advisory
https://lists.debian.org/debian-lts-announce/2018/12/msg00017.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
https://lists.debian.org/debian-lts-announce/2019/11/msg00033.html
https://security.gentoo.org/glsa/201908-05
https://security.gentoo.org/glsa/202006-06
https://usn.ubuntu.com/3877-1/ Third Party Advisory
https://usn.ubuntu.com/4547-1/
https://usn.ubuntu.com/4547-2/
https://usn.ubuntu.com/4587-1/
https://www.debian.org/security/2019/dsa-4383 Third Party Advisory
https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-030-libvnc-heap-out-of-bound-write/ Third Party Advisory
https://lists.debian.org/debian-lts-announce/2018/12/msg00017.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
https://lists.debian.org/debian-lts-announce/2019/11/msg00033.html
https://security.gentoo.org/glsa/201908-05
https://security.gentoo.org/glsa/202006-06
https://usn.ubuntu.com/3877-1/ Third Party Advisory
https://usn.ubuntu.com/4547-1/
https://usn.ubuntu.com/4547-2/
https://usn.ubuntu.com/4587-1/
https://www.debian.org/security/2019/dsa-4383 Third Party Advisory

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Source: NIST National Vulnerability Database (record CVE-2018-20020), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.