MEDIUM
CVE-2020-14403
CWE-787Published: June 17, 2020· Updated: Jun 17, 2026
5.4
CVSS v3.1
Official Description
An issue was discovered in LibVNCServer before 0.9.13. libvncserver/hextile.c allows out-of-bounds access via encodings.
Technical Analysis
CVE-2020-14403 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
From a weakness classification perspective (CWE-787): Out-of-bounds write vulnerabilities can lead to data corruption, crashes, or arbitrary code execution.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityLow
IntegrityNone
AvailabilityLow
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L
Affected Vendors & Products
Canonical1 product(s)
ubuntu linux
Debian1 product(s)
debian linux
libvnc_project1 product(s)
libvncserver
siemens12 product(s)
simatic itc1500 firmwaresimatic itc1500simatic itc1500 pro firmwaresimatic itc1500 prosimatic itc1900 firmwaresimatic itc1900simatic itc1900 pro firmwaresimatic itc1900 prosimatic itc2200 firmwaresimatic itc2200simatic itc2200 pro firmwaresimatic itc2200 pro
Source: NVD CPE · 20 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://usn.ubuntu.com/4434-1/
ADVISORYhttps://usn.ubuntu.com/4573-1/
ADVISORYhttps://usn.ubuntu.com/4434-1/
ADVISORYhttps://usn.ubuntu.com/4573-1/
All References (14)
→
https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdfPatch · Third Party Advisory
→
https://github.com/LibVNC/libvncserver/commit/74e8a70f2c9a5248d6718ce443e07c7ed314dfffPatch · Third Party Advisory
→
https://github.com/LibVNC/libvncserver/compare/LibVNCServer-0.9.12...LibVNCServer-0.9.13Release Notes · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2020/06/msg00035.htmlThird Party Advisory
→
https://lists.debian.org/debian-lts-announce/2020/08/msg00045.htmlMailing List · Third Party Advisory
→
https://usn.ubuntu.com/4434-1/Third Party Advisory
→
https://usn.ubuntu.com/4573-1/Third Party Advisory
→
https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdfPatch · Third Party Advisory
→
https://github.com/LibVNC/libvncserver/commit/74e8a70f2c9a5248d6718ce443e07c7ed314dfffPatch · Third Party Advisory
→
https://github.com/LibVNC/libvncserver/compare/LibVNCServer-0.9.12...LibVNCServer-0.9.13Release Notes · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2020/06/msg00035.htmlThird Party Advisory
→
https://lists.debian.org/debian-lts-announce/2020/08/msg00045.htmlMailing List · Third Party Advisory
→
https://usn.ubuntu.com/4434-1/Third Party Advisory
→
https://usn.ubuntu.com/4573-1/Third Party Advisory
Quick Facts
CVE IDCVE-2020-14403
CVSS Score5.4 / 10
SeverityMEDIUM
WeaknessCWE-787
CISA KEVNo
Affected4 vendor(s)
PublishedJun 17, 2020
Related CVEs (CWE-787)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2020-14403 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.