CVE-2019-8263
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedUltraVNC revision 1205 has stack-based buffer overflow vulnerability in VNC client code inside ShowConnInfo routine, which leads to a denial of service (DoS) condition. This attack appear to be exploitable via network connectivity. User interaction is required to trigger this vulnerability. This vulnerability has been fixed in revision 1206.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceUltraVNC revision 1205 contains a stack-based buffer overflow in the ShowConnInfo routine within the VNC client code. The vulnerability is exploitable via network connectivity but requires user interaction to trigger, leading to a denial of service condition.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 1.2.2.3< 4.8< 14.00<= 12.01CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify UltraVNC installationCheck for UltraVNC installation by looking in Program Files folder for UltraVNC folder, or check Windows Registry under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall for UltraVNC entry, or use 'wmic product get name,version' commandAffected if UltraVNC is found on the system
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Determine UltraVNC versionOpen UltraVNC and go to Help > About, or check the version in the registry key HKLM\SOFTWARE\UltraVNC or examine the file version of winvnc.exe or vncviewer.exe in the installation directoryAffected if The installed version is lower than 1.2.2.3 (for standalone UltraVNC) or the revision number is below 1206
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Identify Siemens Sinumerik software with embedded VNCCheck for Siemens Sinumerik software installations (Sinumerik Access Mymachine, Sinumerik Pcu Base) on the system. Look in Program Files\Siemens or check registry under HKLM\SOFTWARE\Siemens for Sinumerik entriesAffected if Siemens Sinumerik software with bundled VNC component is installed
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Check Siemens software versionFor Siemens Sinumerik Access Mymachine/p2p, verify version is less than 4.8. For Sinumerik Pcu Base Win10, verify version is less than 14.00. For Sinumerik Pcu Base Win7, verify version is 12.01 or lower. Check via registry or program's version infoAffected if The Siemens Sinumerik VNC component version falls within the affected ranges
You are affected if UltraVNC revision 1205 or any version below 1.2.2.3 is installed, or if Siemens Sinumerik software with bundled VNC below the specified version thresholds is present on the system.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data1.2.2.34.814.00
Upgrade UltraVNC to revision 1206 or later to remediate the stack-based buffer overflow vulnerability in the ShowConnInfo routine.
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-8263 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2019-8263 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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