Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2019-20839

26
FAUCET Score

CVE-2019-20839 describes a buffer overflow vulnerability in libvncclient/sockets.c within LibVNCServer versions prior to 0.9.13, affecting products from vendors like Canonical, Debian, and Siemens. This high-severity vulnerability (CVSS 7.5) allows for remote denial-of-service attacks due to unauthenticated input of a long socket filename. While no active exploitation, public exploit code, or significant community discussion has been observed, the potential for a complete system compromise remains.

Impacted Technologies

VendorProductVersion(s)CPE
<= 0.9.12CPE matchmatch criteria
cpe:2.3:a:libvnc_project:libvncserver:*:*:*:*:*:*:*:*
14.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
16.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*
16.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
18.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
3.59%
Probability of exploitation in next 30 days
EPSS Percentile
88.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0359 is in the 79th percentile among its peer group of 51,553 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (3)

github_advisorypatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: libvncserver-0:0.9.11-17.el8
View patch
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: libvncserver

Vendor Advisories (1)

redhatCVE-2019-20839Moderate

libvncserver: buffer overflow in ConnectClientToUnixSock()

Jun 17, 2020

References

lists.opensuse.org / opensuse-security-announce/2020-07/msg00033.html
Mailing ListThird Party Advisory
lists.opensuse.org / opensuse-security-announce/2020-07/msg00055.html
Mailing ListThird Party Advisory
lists.opensuse.org / opensuse-security-announce/2020-07/msg00066.html
Mailing ListThird Party Advisory
cert-portal.siemens.com / productcert/pdf/ssa-390195.pdf
PatchThird Party Advisory
github.com / LibVNC/libvncserver/commit/3fd03977c9b35800d73a865f167338cb4d05b0c1
PatchThird Party Advisory
github.com / LibVNC/libvncserver/compare/LibVNCServer-0.9.12...LibVNCServer-0.9.13
Release NotesThird Party Advisory
lists.debian.org / debian-lts-announce/2020/06/msg00035.html
Mailing ListThird Party Advisory
lists.debian.org / debian-lts-announce/2020/08/msg00045.html
Mailing ListThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/4F6FUH4EFK4NAP6GT4TQRTBKWIRCZLIY
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/NVP7TJVYJDXDFRHVQ3ENEN3H354QPXEZ
usn.ubuntu.com / 4434-1
Third Party Advisory