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UltravncApplication · Uvnc

CVE-2019-8277

HIGH · 7.5 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 →
84/100
Remediation priority · High
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 contains multiple memory leaks (CWE-665) in VNC server code, which allows an attacker to read stack memory and can be abused for information disclosure. Combined with another vulnerability, it can be used to leak stack memory and bypass ASLR. 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 memory leaks (CWE-665) in the VNC server code that allow an attacker to read stack memory via network connectivity. This information disclosure can be combined with other vulnerabilities to bypass ASLR protection.

MitigationUpgrade UltraVNC to revision 1212 or later to patch the memory leak vulnerabilities. Limit network exposure of VNC servers where possible.

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
None
Availability
None

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

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 installed UltraVNC version
    Open Windows Control Panel > Programs and Features, look for UltraVNC in the program list and note the version column. Alternatively, right-click the UltraVNC server tray icon and select 'About' to see the version number.
    Affected if The version shown is earlier than 1.2.2.3 (for example, 1.2.1.x or 1.2.0.x)
  2. Verify VNC server is running
    Open Windows Task Manager, go to the Services tab, and look for 'uvnc_service' or 'UltraVNC Server' in the running services. Alternatively, check if port 5900 (default VNC port) is listening using netstat -an | findstr 5900.
    Affected if The VNC server service is actively running on the system
  3. Confirm product name matches affected list
    In Control Panel > Programs and Features, verify the exact product name is 'UltraVNC' or one of the listed Siemens Sinumerik products (Sinumerik Access Mymachine/p2p, Sinumerik Pcu Base Win10 Software/ipc, Sinumerik Pcu Base Win7 Software/ipc).
    Affected if The product name matches UltraVNC or any Siemens Sinumerik variant with version < 1.2.2.3 (for UltraVNC) or the specified version thresholds for Siemens products
  4. Check for Siemens Sinumerik installation
    If the system is a Siemens industrial PC, open Siemens SIMATIC Management Console or check Program Files for 'Siemens\Sinumerik' directory. Look for version files or check Windows Registry under HKLM\SOFTWARE\Siemens\SINUMERIK for installed version information.
    Affected if A Siemens Sinumerik product is installed with version below 4.8 (Access Mymachine), below 14.00 (Pcu Base Win10), or at/below 12.01 (Pcu Base Win7)
  5. Verify network accessibility of VNC service
    From a remote system, attempt to connect to the VNC port (typically 5900) using a VNC client or run telnet <target_ip> 5900 to confirm the port is open and responding.
    Affected if The VNC server port is accessible from network (non-localhost) which enables remote exploitation of the memory leak

You are affected if UltraVNC version is lower than 1.2.2.3 (or a Siemens Sinumerik variant with version below its threshold) AND the VNC server component is running and network-accessible.

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 1212 or later to patch the memory leak vulnerabilities. Limit network exposure of VNC servers where possible.

Fix this in Ultravnc Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,440
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,304.

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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-2019-8277 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