HIGH
CVE-2018-21247
CWE-909Published: June 17, 2020· Updated: Jun 17, 2026
7.5
CVSS v3.1
Official Description
An issue was discovered in LibVNCServer before 0.9.13. There is an information leak (of uninitialized memory contents) in the libvncclient/rfbproto.c ConnectToRFBRepeater function.
Technical Analysis
CVE-2018-21247 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in complete confidentiality breach (data exposure), with a CVSS base score of 7.5.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Affected Vendors & Products
Canonical1 product(s)
ubuntu linux
Debian1 product(s)
debian linux
libvnc_project1 product(s)
libvncserver
openSUSE1 product(s)
leap
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
All References (16)
→
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00033.htmlMailing List · Third Party Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00055.htmlMailing List · Third Party Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00066.htmlMailing List · Third Party Advisory
→
https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdfPatch · Third Party Advisory
→
https://github.com/LibVNC/libvncserver/compare/LibVNCServer-0.9.12...LibVNCServer-0.9.13Patch · Third Party Advisory
→
https://github.com/LibVNC/libvncserver/issues/253Issue Tracking · Third Party Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00033.htmlMailing List · Third Party Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00055.htmlMailing List · Third Party Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00066.htmlMailing List · Third Party Advisory
→
https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdfPatch · Third Party Advisory
→
https://github.com/LibVNC/libvncserver/compare/LibVNCServer-0.9.12...LibVNCServer-0.9.13Patch · Third Party Advisory
→
https://github.com/LibVNC/libvncserver/issues/253Issue Tracking · Third Party Advisory
Quick Facts
CVE IDCVE-2018-21247
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-909
CISA KEVNo
Affected5 vendor(s)
PublishedJun 17, 2020
Related CVEs (CWE-909)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2018-21247 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.