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Classic Buffer OverflowWeakness · CWE-120

CVE-2023-50821

MEDIUM · 6.2 CVSS v3.1 Published 2024-04-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
67/100
Remediation priority · Elevated
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 PCS 7 V9.1 (All versions < V9.1 SP2 UC04), SIMATIC WinCC Runtime Professional V17 (All versions < V17 Update 8), SIMATIC WinCC Runtime Professional V18 (All versions < V18 Update 4), SIMATIC WinCC Runtime Professional V19 (All versions < V19 Update 1), SIMATIC WinCC V7.5 (All versions < V7.5 SP2 Update 16), SIMATIC WinCC V8.0 (All versions < V8.0 Update 5). The affected products do not properly validate the input provided in the login dialog box. An attacker could leverage this vulnerability to cause a persistent denial of service 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

The vulnerability exists in the login dialog box input validation of SIMATIC PCS 7 V9.1 and multiple versions of SIMATIC WinCC (V7.5, V8.0, V17, V18, V19). Improper validation of login input allows an attacker to trigger a persistent denial of service condition, likely through malformed input causing the service to crash or become unresponsive.

MitigationApply vendor-supplied patches: Update SIMATIC PCS 7 to V9.1 SP2 UC04, WinCC V7.5 to SP2 Update 16, WinCC V8.0 to Update 5, WinCC V17 to Update 8, WinCC V18 to Update 4, and WinCC V19 to Update 1.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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
Local
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/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 installed SIMATIC product
    Check installed programs or program directories for SIMATIC WinCC or SIMATIC PCS 7. Look for Siemens automation software listings in Windows Programs and Features or the installation directory (commonly C:\Program Files\Siemens).
    Affected if Neither WinCC nor PCS 7 is installed, then the environment is not affected.
  2. Determine WinCC version
    If WinCC is installed, locate the version information. In the WinCC installation folder, check the file version of the main executable (e.g., WinCC.exe) or review the program properties in Programs and Features.
    Affected if The installed version is V7.5, V8.0, V17, V18, or V19 and is below the fixed versions (SP2 Update 16 for V7.5, Update 5 for V8.0, Update 8 for V17, Update 4 for V18, Update 1 for V19).
  3. Determine PCS 7 version
    If SIMATIC PCS 7 is installed, locate the version information through the SIMATIC Manager or check the installed programs listing for the PCS 7 version and service pack.
    Affected if The installed version is V9.1 without SP2 UC04 applied.
  4. Verify login service accessibility
    Determine if the WinCC or PCS 7 Runtime/login interface is network-accessible or exposed to untrusted users. Check firewall rules and network segmentation around the engineering station or runtime server.
    Affected if The login dialog is exposed to network users or untrusted personnel, increasing the likelihood of exploitation.

A defender is affected if SIMATIC WinCC V7.5 through V19 or SIMATIC PCS 7 V9.1 is installed with a version below the patched releases and the login interface is accessible to potential attackers.

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 PCS 7 to V9.1 SP2 UC04, WinCC V7.5 to SP2 Update 16, WinCC V8.0 to Update 5, WinCC V17 to Update 8, WinCC V18 to Update 4, and WinCC V19 to Update 1.

Recommended fix High confidence

Upgrade to the minimum fixed version specific to your product: SIMATIC PCS 7 V9.1 SP2 UC04, WinCC Runtime Professional V17 Update 8, V18 Update 4, or V19 Update 1, WinCC V7.5 SP2 Update 16, or WinCC V8.0 Update 5

  1. 1. Identify the specific SIMATIC product and version currently installed in your environment.
  2. 2. For SIMATIC PCS 7 V9.1 users: Upgrade to version V9.1 SP2 UC04 or later.
  3. 3. For SIMATIC WinCC Runtime Professional V17 users: Upgrade to version V17 Update 8 or later.
  4. 4. For SIMATIC WinCC Runtime Professional V18 users: Upgrade to version V18 Update 4 or later.
  5. 5. For SIMATIC WinCC Runtime Professional V19 users: Upgrade to version V19 Update 1 or later.
  6. 6. For SIMATIC WinCC V7.5 users: Upgrade to version V7.5 SP2 Update 16 or later.
  7. 7. For SIMATIC WinCC V8.0 users: Upgrade to version V8.0 Update 5 or later.
  8. 8. Obtain updates from Siemens via their official support channels or Siemens Industry Online Support portal.
Caveat Review Siemens release notes for your specific version upgrade as there may be compatibility considerations with existing projects and dependent systems

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-2023-50821 in production — separate from our analysis above.

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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
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  • Version or environment caveats, and links to real fixes
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