dbcve.org
Simatic Pcs 7Application · Siemens

CVE-2021-40358

CRITICAL · 9.9 CVSS v3.1 Published 2021-11-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable 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 PCS 7 V8.2 (All versions), SIMATIC PCS 7 V9.0 (All versions < V9.0 SP3 UC04), SIMATIC PCS 7 V9.1 (All versions < V9.1 SP1), SIMATIC WinCC V15 and earlier (All versions < V15 SP1 Update 7), SIMATIC WinCC V16 (All versions < V16 Update 5), SIMATIC WinCC V17 (All versions < V17 Update 2), SIMATIC WinCC V7.4 (All versions < V7.4 SP1 Update 19), SIMATIC WinCC V7.5 (All versions < V7.5 SP2 Update 5). Legitimate file operations on the web server of the affected systems do not properly neutralize special elements within the pathname. An attacker could then cause the pathname to resolve to a location outside of the restricted directory on the server and read, write or delete unexpected critical files.

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 path traversal vulnerability exists in the web server components of SIMATIC PCS 7 and WinCC. The file operation functions fail to properly sanitize special path elements, allowing attackers to use '..' sequences to escape the restricted directory and access, modify, or delete arbitrary files on the server filesystem.

MitigationApply vendor-supplied patches: update SIMATIC WinCC to V15 SP1 Update 7/V16 Update 5/V17 Update 2/V7.4 SP1 Update 19/V7.5 SP2 Update 5 or later; update SIMATIC PCS 7 to V9.0 SP3 UC04 or V9.1 SP1 or later. If patching is not immediately possible, disable the web server component or restrict network access to trusted IPs.

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 Pcs 7Application
Affected:= 8.2= 9.0= 9.1
Simatic WinccApplication
Affected:= 7.4= 7.5= 15= 15.1= 16= 17

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
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/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 installed product and version
    Check Windows installed programs or registry for Siemens SIMATIC WinCC or SIMATIC PCS 7 version. In Windows, open Programs and Features or check HKEY_LOCAL_MACHINE\SOFTWARE\Siemens\Automation\InstalledProducts in the registry.
    Affected if The installed version matches 8.2, 9.0, or 9.1 for PCS 7; or 7.4, 7.5, 15, 15.1, 16, or 17 for WinCC.
  2. Verify web server component is enabled
    Check if the SIMATIC WinCC Web Navigator or PCS 7 Web Server service is running. Use Windows Services console (services.msc) or PowerShell: Get-Service | Where-Object {$_.Name -like '*Web*' -and $_.Name -like '*SIMATIC*'}.
    Affected if The web server component is installed and running.
  3. Check web server configuration
    Locate the web server configuration files, typically in the WinCC or PCS 7 installation directory under Web\Config or similar web subdirectory. Inspect configuration files for any path settings or access controls.
    Affected if Web server is present and configured to allow file operations.
  4. Review web server access logs
    Examine web server log files in the web server logs directory for requests containing '..' path sequences. Look for patterns like '../' or '..\' in HTTP requests.
    Affected if Log entries show path traversal attempts with '..' sequences targeting the web server.

The system is affected if it runs an affected version of SIMATIC PCS 7 (8.2, 9.0, or 9.1) or WinCC (7.4, 7.5, 15, 15.1, 16, or 17) with the web server component 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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor-supplied patches: update SIMATIC WinCC to V15 SP1 Update 7/V16 Update 5/V17 Update 2/V7.4 SP1 Update 19/V7.5 SP2 Update 5 or later; update SIMATIC PCS 7 to V9.0 SP3 UC04 or V9.1 SP1 or later. If patching is not immediately possible, disable the web server component or restrict network access to trusted IPs.

Recommended fix High confidence

SIMATIC WinCC: V7.4->V7.4 SP1 Update 19, V7.5->V7.5 SP2 Update 5, V15->V15 SP1 Update 7, V16->V16 Update 5, V17->V17 Update 2; SIMATIC PCS 7: V9.0->V9.0 SP3 UC04, V9.1->V9.1 SP1

  1. 1. Identify the exact installed version of SIMATIC PCS 7 or WinCC in your environment
  2. 2. For SIMATIC WinCC V7.4: Upgrade to V7.4 SP1 Update 19 or later
  3. 3. For SIMATIC WinCC V7.5: Upgrade to V7.5 SP2 Update 5 or later
  4. 4. For SIMATIC WinCC V15 and earlier: Upgrade to V15 SP1 Update 7 or later
  5. 5. For SIMATIC WinCC V16: Upgrade to V16 Update 5 or later
  6. 6. For SIMATIC WinCC V17: Upgrade to V17 Update 2 or later
  7. 7. For SIMATIC PCS 7 V9.0: Upgrade to V9.0 SP3 UC04 or later
  8. 8. For SIMATIC PCS 7 V9.1: Upgrade to V9.1 SP1 or later
Caveat Major version upgrades may require testing of existing projects; backup all configurations before applying updates

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

Fix this in Simatic Pcs 7 Scoped from the published advisory
  • Consultation8.0 h
  • Implementation12.0 h
  • Testing16.0 h
  • Review / QA8.0 h
44.0 hours of engineering $7,600
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $12,160.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-40358 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2021-40358 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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