HOMEVULNERABILITIESCVE-2019-8268
CRITICAL

CVE-2019-8268

CWE-193Published: March 8, 2019· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official Description

UltraVNC revision 1206 has multiple off-by-one vulnerabilities in VNC client code connected with improper usage of ClientConnection::ReadString function, which can potentially result code execution. This attack appears to be exploitable via network connectivity. These vulnerabilities have been fixed in revision 1207.

NVD Source

Technical Analysis

CVE-2019-8268 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), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

siemens3 product(s)
sinumerik access mymachine\/p2psinumerik pcu base win10 software\/ipcsinumerik pcu base win7 software\/ipc
uvnc1 product(s)
ultravnc
Source: NVD CPE · 4 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://cert-portal.siemens.com/productcert/pdf/ssa-927095.pdf
ADVISORYhttps://ics-cert.kaspersky.com/advisories/klcert-advisories/2019/03/01/klcert-19-015-ultravnc-off-by-one-error/
ADVISORYhttps://www.us-cert.gov/ics/advisories/icsa-20-161-06
ADVISORYhttps://cert-portal.siemens.com/productcert/pdf/ssa-927095.pdf
ADVISORYhttps://ics-cert.kaspersky.com/advisories/klcert-advisories/2019/03/01/klcert-19-015-ultravnc-off-by-one-error/
ADVISORYhttps://www.us-cert.gov/ics/advisories/icsa-20-161-06

All References (6)

→
https://cert-portal.siemens.com/productcert/pdf/ssa-927095.pdfThird Party Advisory
→
https://ics-cert.kaspersky.com/advisories/klcert-advisories/2019/03/01/klcert-19-015-ultravnc-off-by-one-error/Third Party Advisory
→
https://www.us-cert.gov/ics/advisories/icsa-20-161-06Third Party Advisory · US Government Resource
→
https://cert-portal.siemens.com/productcert/pdf/ssa-927095.pdfThird Party Advisory
→
https://ics-cert.kaspersky.com/advisories/klcert-advisories/2019/03/01/klcert-19-015-ultravnc-off-by-one-error/Third Party Advisory
→
https://www.us-cert.gov/ics/advisories/icsa-20-161-06Third Party Advisory · US Government Resource

Quick Facts

CVE IDCVE-2019-8268
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-193
CISA KEVNo
Affected2 vendor(s)
PublishedMar 8, 2019

Related CVEs (CWE-193)

CVE-2025-54349
10.0
CVE-2024-10442
10.0
CVE-2020-10062
9.8
CVE-2019-14532
9.8
CVE-2020-8443
9.8
CVE-2018-8828
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2019-8268 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.COM. CVE data is provided under the NVD usage policy.
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