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UltravncApplication · Uvnc

CVE-2019-8262

CRITICAL · 9.8 CVSS v3.1 Published 2019-03-05
Fix available
A fix is available. Upgrade to 1.2.2.3 / 4.8 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 · unedited
UltraVNC revision 1203 has multiple heap buffer overflow vulnerabilities in VNC client code inside Ultra decoder, which results in code execution. This attack appears to be exploitable via network connectivity. These vulnerabilities have been fixed in revision 1204.

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 confidence

Multiple heap buffer overflow vulnerabilities exist in UltraVNC revision 1203's Ultra decoder within the VNC client code. These flaws allow remote code execution via network connectivity, making them critically severe.

MitigationUpgrade UltraVNC to revision 1204 or later to address the heap buffer overflows in the Ultra decoder component.

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
UltravncApplication
Affected:< 1.2.2.3
Sinumerik Access Mymachine\/p2pApplication
Affected:< 4.8
Sinumerik Pcu Base Win10 Software\/ipcApplication
Affected:< 14.00
Sinumerik Pcu Base Win7 Software\/ipcApplication
Affected:<= 12.01

CVSS 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
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify UltraVNC installation and version
    Check the UltraVNC executable version. On Windows, right-click uvnc.exe or winvnc.exe in the installation directory (commonly C:\Program Files\UltraVNC or C:\Program Files (x86)\UltraVNC), select Properties, and view the Version tab. Alternatively, run 'wmic product get name,version' or check the registry key HKEY_LOCAL_MACHINE\SOFTWARE\UltraVNC or HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\UltraVNC for the InstallVersion value.
    Affected if The installed version is earlier than 1.2.2.3 (revision 1204 and later are fixed).
  2. Confirm UltraVNC service is running
    Open Services (services.msc) and check if the 'uvnc_service' or 'winvnc' service is running, or run 'sc query winvnc' or 'netstat -an | findstr 5900' to check if the VNC server listening on port 5900 is active.
    Affected if The service is running and accepting connections, making the vulnerable Ultra decoder component active.
  3. Verify Ultra encoding is enabled in configuration
    Check the UltraVNC configuration file (ultravnc.ini or settings.ini in the UltraVNC installation folder or %APPDATA%\UltraVNC) for the 'Encoder' or 'PollFullScreen' settings, or open UltraVNC Server Settings and verify if 'Ultra Encoding' is checked under the 'Encoding' tab.
    Affected if Ultra Encoding is enabled, as the vulnerability exists in the Ultra decoder component that processes this encoding.
  4. Check Siemens Sinumerik product versions if applicable
    If running Siemens Sinumerik software (Access Mymachine/P2P, Pcu Base Win10 Software/IPC, or Pcu Base Win7 Software/IPC), check the installed version via Add/Remove Programs, the software's About/Help dialog, or by locating the embedded UltraVNC components in the Siemens installation directories.
    Affected if The Siemens product version is below 4.8 (for Access Mymachine), below 14.00 (for Win10 IPC), or 12.01 or earlier (for Win7 IPC).

A system is affected if it runs UltraVNC version earlier than 1.2.2.3 (or the corresponding Siemens product versions) with the Ultra encoder/decoder component active and enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Upgrade available Upgrade to 1.2.2.3 / 4.8 / 14.00 or later
Fixed in 1.2.2.34.814.00
Interim mitigation

Upgrade UltraVNC to revision 1204 or later to address the heap buffer overflows in the Ultra decoder component.

Fix this in Ultravnc Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,224.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2019-8262 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data