ICSA-26-174-02: Siemens SIPROTEC 5 Using DIGSI5 Protocol

CISA's summary

Summary: SIPROTEC 5 is vulnerable to arbitrary file uploads by authenticated users using the DIGSI 5 protocol. This could allow an attacker to upload malicious configuration files, potentially causing a permanent denial of service condition. As a mitigation measure, users of the CP050 and CP150 device models are advised to upgrade to version 9.90 or later. For CP300 device models, devices 7ST85 and 7ST86 are advised to upgrade to version 10.00 or later, while the remaining models should upgrade to version 9.90 or later. These versions introduce an allow-list feature that restricts arbitrary file uploads and reduces the risk associated with this vulnerability. Siemens is preparing fix versions and recommends specific countermeasures for products where fixes are not, or not yet available.

Products, as the advisory lists them

DeSpy has not checked any unit, hardware revision or firmware.

Vulnerabilities in this advisory

• CVE-2025-40808 — CVE-2025-40808 · CWE-434

  The affected application allows authenticated users to upload arbitrary files using DIGSI 5 protocol. This could allow an attacker to upload malicious configuration files, that could cause denial of service condition and potentially lead to code execution.

Acknowledgments, as the advisory lists them

• Siemens ProductCERT: reported this vulnerability to CISA.

The advisory's legal notice

The use of Siemens Security Advisories is subject to the terms and conditions listed on: https://www.siemens.com/productcert/terms-of-use.

Sources

• The advisory at cisa.gov
• The CSAF document (JSON)

DeSpy's copy of this version is dated 2026-09-28.