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NULL Pointer DereferenceWeakness · CWE-476

CVE-2023-30756

MEDIUM · 5.9 CVSS v3.1 Published 2024-09-10
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
68/100
Remediation priority · Elevated
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 CP 1242-7 V2 (incl. SIPLUS variants) (All versions < V3.5.20), SIMATIC CP 1243-1 (incl. SIPLUS variants) (All versions < V3.5.20), SIMATIC CP 1243-1 DNP3 (incl. SIPLUS variants) (All versions < V3.5.20), SIMATIC CP 1243-1 IEC (incl. SIPLUS variants) (All versions < V3.5.20), SIMATIC CP 1243-7 LTE (All versions < V3.5.20), SIMATIC CP 1243-8 IRC (6GK7243-8RX30-0XE0) (All versions < V3.5.20), SIMATIC HMI Comfort Panels (incl. SIPLUS variants) (All versions), SIMATIC IPC DiagBase (All versions), SIMATIC IPC DiagMonitor (All versions), SIMATIC WinCC Runtime Advanced (All versions), SIPLUS TIM 1531 IRC (6AG1543-1MX00-7XE0) (All versions < V2.4.8), TIM 1531 IRC (6GK7543-1MX00-0XE0) (All versions < V2.4.8). The web server of the affected devices do not properly handle certain errors when using the Expect HTTP request header, resulting in NULL dereference. This could allow a remote attacker with no privileges to cause a denial of service condition in the system.

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 web server component in affected Siemens SIMATIC devices fails to properly handle error conditions when processing the HTTP Expect request header, leading to a NULL pointer dereference. A remote unauthenticated attacker can send specially crafted HTTP requests with the Expect header to trigger this condition, causing the web service to crash and resulting in denial of service.

MitigationApply vendor-supplied firmware updates: upgrade SIMATIC CP 1242-7 V2, CP 1243-1 variants, CP 1243-7 LTE, and CP 1243-8 IRC to version V3.5.20 or later; upgrade TIM 1531 IRC variants to V2.4.8 or later. For HMI Comfort Panels, IPC DiagBase, IPC DiagMonitor, and WinCC Runtime Advanced (listed as 'all versions' affected), contact Siemens for available patches or mitigations.

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
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:H/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 SIMATIC device model
    Access the device's web interface or check the device label/management console to determine the exact model (e.g., CP 1242-7 V2, CP 1243-1, CP 1243-7 LTE, CP 1243-8 IRC, TIM 1531 IRC, HMI Comfort Panel, IPC DiagBase, IPC DiagMonitor, or WinCC Runtime Advanced)
    Affected if The device model matches any of the affected products listed in the CVE
  2. Verify the web server component is enabled
    Access the device configuration (via web interface, TIA Portal, or device management) and check if the web server/HTTP server feature is activated. This is typically found under 'Web Server' settings in the device properties
    Affected if The web server is enabled and accessible over the network
  3. Determine the installed firmware version
    Check the device's firmware version through the web interface (usually displayed on the landing page or in system info), or via the management console/PLC programming software. For CP modules, check via the device's web pages or STEP 7/TIA Portal. For TIM devices, check via the web interface or management. For HMI/IPC products, check via the control panel or system information
    Affected if The firmware version cannot be determined or is below V3.5.20 for CP 1242-7/CP 1243-1/CP 1243-7 LTE/CP 1243-8 IRC, below V2.4.8 for TIM 1531 IRC, or is any version for HMI Comfort Panels, IPC DiagBase, IPC DiagMonitor, or WinCC Runtime Advanced
  4. Confirm HTTP service availability
    Send a test HTTP request to the device's web server IP address on port 80 or 443 to verify the web service is reachable. Use a tool like curl or a browser to confirm the service is running
    Affected if The web server responds to HTTP requests, indicating it is actively running and potentially exposed

The environment is affected if the device is one of the listed SIMATIC products, has its web server enabled and accessible, and runs a firmware version below the fixed releases (or any version for the 'all versions' products).

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 firmware updates: upgrade SIMATIC CP 1242-7 V2, CP 1243-1 variants, CP 1243-7 LTE, and CP 1243-8 IRC to version V3.5.20 or later; upgrade TIM 1531 IRC variants to V2.4.8 or later. For HMI Comfort Panels, IPC DiagBase, IPC DiagMonitor, and WinCC Runtime Advanced (listed as 'all versions' affected), contact Siemens for available patches or mitigations.

Recommended fix High confidence

For SIMATIC CP 1242-7 V2, CP 1243-1, CP 1243-1 DNP3, CP 1243-1 IEC, CP 1243-7 LTE, CP 1243-8 IRC: upgrade to V3.5.20 or later; For TIM 1531 IRC: upgrade to V2.4.8 or later; For HMI Comfort Panels, IPC DiagBase, IPC DiagMonitor, WinCC Runtime Advanced: apply vendor patch when available

  1. 1. Identify the specific affected device model from the list (SIMATIC CP 1242-7 V2, CP 1243-1, CP 1243-1 DNP3, CP 1243-1 IEC, CP 1243-7 LTE, CP 1243-8 IRC, HMI Comfort Panels, IPC DiagBase, IPC DiagMonitor, WinCC Runtime Advanced, or TIM 1531 IRC)
  2. 2. Navigate to Siemens Industry Online Support (support.industry.siemens.com)
  3. 3. Locate the firmware/software download page for your specific device
  4. 4. Download the latest firmware version: For CP 1242-7 V2, CP 1243-1 variants, CP 1243-7 LTE, and CP 1243-8 IRC - download version V3.5.20 or later
  5. 5. Download the latest firmware version: For TIM 1531 IRC (6GK7543-1MX00-0XE0 and 6AG1543-1MX00-7XE0) - download version V2.4.8 or later
  6. 6. For SIMATIC HMI Comfort Panels, IPC DiagBase, IPC DiagMonitor, and WinCC Runtime Advanced - contact Siemens directly for patches as these are listed as 'All versions' affected
  7. 7. Follow Siemens firmware update instructions specific to your device (typically via TIA Portal, STEP 7, or web-based firmware update)
  8. 8. After updating, verify the web server functionality and confirm the vulnerability is remediated
Caveat Industrial device firmware upgrades may require downtime and should be tested in a staging environment before production deployment; ensure compatibility with existing automation projects

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

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2023-30756 in production — separate from our analysis above.

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