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Simatic Wincc Runtime AdvancedApplication · Siemens

CVE-2021-27385

HIGH · 7.5 CVSS v3.1 Published 2021-05-12
Fix available
A fix is available. Upgrade to 15.1 / 16 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
A vulnerability has been identified in SIMATIC HMI Comfort Outdoor Panels V15 7\" & 15\" (incl. SIPLUS variants) (All versions < V15.1 Update 6), SIMATIC HMI Comfort Outdoor Panels V16 7\" & 15\" (incl. SIPLUS variants) (All versions < V16 Update 4), SIMATIC HMI Comfort Panels V15 4\" - 22\" (incl. SIPLUS variants) (All versions < V15.1 Update 6), SIMATIC HMI Comfort Panels V16 4\" - 22\" (incl. SIPLUS variants) (All versions < V16 Update 4), SIMATIC HMI KTP Mobile Panels V15 KTP400F, KTP700, KTP700F, KTP900 and KTP900F (All versions < V15.1 Update 6), SIMATIC HMI KTP Mobile Panels V16 KTP400F, KTP700, KTP700F, KTP900 and KTP900F (All versions < V16 Update 4), SIMATIC WinCC Runtime Advanced V15 (All versions < V15.1 Update 6), SIMATIC WinCC Runtime Advanced V16 (All versions < V16 Update 4), SINAMICS GH150 (All versions), SINAMICS GL150 (with option X30) (All versions), SINAMICS GM150 (with option X30) (All versions), SINAMICS SH150 (All versions), SINAMICS SL150 (All versions), SINAMICS SM120 (All versions), SINAMICS SM150 (All versions), SINAMICS SM150i (All versions). A remote attacker could send specially crafted packets to SmartVNC device layout handler on client side, which could influence the amount of resources consumed and result in a Denial-of-Service (infinite loop) condition.

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

A remote attacker can send specially crafted packets to the SmartVNC device layout handler on affected Siemens SIMATIC HMI panels and SINAMICS drives, causing an infinite loop that consumes excessive resources and results in denial-of-service conditions.

MitigationApply vendor-supplied updates (V15.1 Update 6 or later for V15 products, V16 Update 4 or later for V16 products) to all affected devices. Implement network segmentation and firewall rules to restrict unauthorized access to SmartVNC services.

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
Simatic Wincc Runtime AdvancedApplication
Affected:< 16= 16< 15.1= 15.1
Sinamics Sh150 FirmwareOperating system
Affected:all versions
Sinamics Sm150i FirmwareOperating system
Affected:all versions
Sinamics Gh150 FirmwareOperating system
Affected:all versions
Sinamics Gl150 FirmwareOperating system
Affected:all versions
Sinamics Gm150 FirmwareOperating system
Affected:all versions
Sinamics Sl150 FirmwareOperating system
Affected:all versions
Sinamics Sm120 FirmwareOperating system
Affected:all versions

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
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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 checks

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

  1. Identify the installed Siemens product
    Locate the Siemens SIMATIC HMI panel or SINAMICS drive in your environment. Check the system documentation, device management console, or the device itself for product name and model information.
    Affected if The product is any of: Simatic Wincc Runtime Advanced, Sinamics Sh150, Sinamics Sm150i, Sinamics Gh150, Sinamics Gl150, Sinamics Gm150, Sinamics Sl150, or Sinamics Sm120.
  2. Check WinCC Runtime Advanced version
    For Simatic WinCC Runtime Advanced, open the system information or check the installed programs list. The version is typically visible in the application properties or Siemens Start Menu entry. Compare your version against the affected ranges: any version < 16, exactly version 16, any version < 15.1, or exactly version 15.1.
    Affected if The installed version is 15.1, any version below 15.1, or version 16 (including versions below 16).
  3. Check Sinamics firmware version
    For Sinamics drives (Sh150, Sm150i, Gh150, Gl150, Gm150, Sl150, Sm120), access the drive via its web interface, SINAMICS Startdrive, or the device front panel. Navigate to the firmware version information section. The firmware version is typically displayed as a numerical value.
    Affected if Any firmware version is installed on Sinamics Sh150, Sm150i, Gh150, Gl150, Gm150, Sl150, or Sm120 drives.
  4. Verify SmartVNC service status
    Check if SmartVNC is enabled or accessible on the device. For WinCC Runtime Advanced, examine the VNC server settings in the project configuration or check if port 5900 (default SmartVNC port) is open and listening. For Sinamics devices, check the VNC or remote access settings in the drive configuration.
    Affected if SmartVNC is enabled, configured, or accessible via network on the affected device.

You are affected if you run Simatic WinCC Runtime Advanced versions 15.1 or 16 (or any version below these), or any Sinamics firmware version on the listed models, and SmartVNC is enabled or 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 15.1 / 16 or later
Fixed in 15.116
Interim mitigation

Apply vendor-supplied updates (V15.1 Update 6 or later for V15 products, V16 Update 4 or later for V16 products) to all affected devices. Implement network segmentation and firewall rules to restrict unauthorized access to SmartVNC services.

Fix this in Simatic Wincc Runtime Advanced Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
36.0 hours of engineering $6,400
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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-2021-27385 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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