CVE-2025-26389 Siemens CVE debrief

Who should care

OT/ICS operators and security teams running Siemens OZW672 or OZW772, especially any environment where the web service is reachable from untrusted networks. System integrators, asset owners, and defenders responsible for patching or segmenting Siemens building or industrial control assets should prioritize this advisory.

Technical summary

The advisory describes an input-sanitization failure in the `exportDiagramPage` endpoint of affected Siemens web services. The resulting impact is unauthenticated remote code execution with root privileges. The supplied CVSS vector is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H, indicating a high-severity network-reachable issue with no privileges required and no user interaction needed.

Defensive priority

Immediate. This is a critical, network-reachable RCE affecting OT-facing web services, with no authentication required and full confidentiality, integrity, and availability impact stated in the advisory.

Recommended defensive actions

• Apply the vendor fix and update affected devices to V8.0 or later, as specified in the Siemens remediation guidance.
• Inventory Siemens OZW672 and OZW772 assets and confirm whether the affected web service is deployed or exposed.
• Restrict network access to the web interface and place affected devices behind appropriate segmentation and access controls.
• Review the Siemens and CISA advisory references for product-specific remediation guidance before maintenance windows.
• Validate remediation after patching by confirming the device reports the intended version and that the web service exposure is reduced.

Evidence notes

The debrief is based on the supplied CISA CSAF source item for ICSA-25-135-10 and the embedded Siemens references. The source explicitly states that unsanitized input parameters in `exportDiagramPage` can enable an unauthenticated remote attacker to execute arbitrary code with root privileges. Product scope, remediation version, and severity vector were taken from the provided corpus only.

Official resources