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UltravncApplication · Uvnc

CVE-2019-8275

CRITICAL · 9.8 CVSS v3.1 Published 2019-03-08
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 1211 has multiple improper null termination vulnerabilities in VNC server code, which result in out-of-bound data being accessed by remote users. This attack appears to be exploitable via network connectivity. These vulnerabilities have been fixed in revision 1212.

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

UltraVNC revision 1211 contains multiple improper null termination vulnerabilities in the VNC server code. These flaws cause out-of-bounds data to be accessed by remote users due to strings not being properly null-terminated, leading to potential information disclosure or memory corruption over network connectivity.

MitigationUpgrade UltraVNC to revision 1212 or later to address the null termination vulnerabilities. Restrict network access to VNC servers until the patch is applied.

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 server installation
    Check for UltraVNC server installation by examining installed programs in Windows Control Panel > Programs and Features, or check for the presence of vncserver.exe or winvnc.exe in common installation directories such as C:\Program Files\UltraVNC or C:\Program Files (x86)\UltraVNC
    Affected if UltraVNC server is installed and the version is lower than 1.2.2.3
  2. Determine UltraVNC version number
    Right-click the UltraVNC server icon in the system tray and select 'About' to view the version, or right-click the winvnc.exe file in the installation folder and select 'Properties' > 'Details' to see the file version
    Affected if The reported version is below 1.2.2.3, indicating the vulnerable version is installed
  3. Identify Siemens Sinumerik software presence
    Check Windows Control Panel > Programs and Features for installed Siemens Sinumerik applications such as Sinumerik Access Mymachine, Sinumerik Pcu Base Win10 Software, or Sinumerik Pcu Base Win7 Software
    Affected if Any Siemens Sinumerik software listed has a version below 4.8 (for Access Mymachine/p2p), below 14.00 (for Win10), or at or below 12.01 (for Win7)
  4. Verify VNC server is running and listening
    Open Command Prompt and run 'netstat -an | findstr :5900' to check if the VNC server port 5900 is listening, or use Task Manager to verify winvnc.exe or vncserver.exe process is active
    Affected if The VNC server process is running and bound to a network port, exposing the vulnerable code to network attackers

You are affected if UltraVNC version is below 1.2.2.3 or Siemens Sinumerik software is below the specified version thresholds, and the VNC server is running and accessible over the network.

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.

dbcve · scoped
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 1212 or later to address the null termination vulnerabilities. Restrict network access to VNC servers until the patch is applied.

Recommended fix High confidence

UltraVNC revision 1212 (version 1.2.2.3) or corresponding fixed versions of Sinumerik products

  1. 1. Identify the installed UltraVNC version or determine if the Sinumerik product uses an affected UltraVNC component
  2. 2. For direct UltraVNC installations: upgrade to revision 1212 (also labeled as version 1.2.2.3)
  3. 3. For Sinumerik Access Mymachine/p2p: upgrade to version 4.8 or later
  4. 4. For Sinumerik Pcu Base Win10 Software/ipc: upgrade to version 14.00 or later
  5. 5. For Sinumerik Pcu Base Win7 Software/ipc: upgrade to a version newer than 12.01
  6. 6. Verify the upgrade was successful by checking the VNC server version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Ultravnc Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
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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-2019-8275 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