CVE-2019-20839

mediumpriority · track · 31EPSS 0.036 · 89 %ileDEEURUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
3.59% (89th) EPSS
CVSS 5 · medium
Is it mine?
74 products
Check your exposure
Who says so?
6 sources
cnnvd · enisa_euvd · fstec_bdu · cisa_csaf_ot

EPSS · scored 2026-10-27

libvncclient/sockets.c in LibVNCServer before 0.9.13 has a buffer overflow via a long socket filename.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

02

cvss

Technical severity, 0–10. One row per scoring source.

7.5
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5–7.5

v2.05mediumAV:N/AC:L/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 10 · impact 2.9
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:Csecondary · CISA US
v3.17.5highAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:Csecondary · Siemens ProductCERT DE
v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · Red Hat Product Security US
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-120USprimaryCWE-120USCWE-120USCWE-120USCWE-120US
04

affected products (74)

Products and version ranges known to be affected.

showing 20 of 74
05

advisories (3)

Vendor and ecosystem advisories describing this.

  • RHSA-2021:1811Red Hat Security Advisory: libvncserver security update2021-05-18csaf · redhat_csafUS

    An update for libvncserver is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

  • SSA-390195SSA-390195: LibVNC Vulnerabilities in SIMATIC ITC Products2021-12-14csaf · siemens_psirtDE

    Multiple LibVNC vulnerabilities in the affected products listed below could allow remote code execution, information disclosure and Denial-of-Service attacks under certain conditions. Siemens has released updates for the affected products and recommends to update to the latest versions.

  • ICSA-21-350-12Siemens SIMATIC ITC2021-12-14icsa · cisa_csaf_otUS

    Multiple LibVNC vulnerabilities in the affected products listed below could allow remote code execution, information disclosure and Denial-of-Service attacks under certain conditions. Siemens has released updates for the affected products and recommends to update to the latest versions.

06

also known as (4)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bducisa_csaf_otredhat_csafsiemens_psirtNVDCVE.orgMITRE
published 2020-06-17modified 2026-06-17
09

references (45)

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan