ICSA-26-071-04: Siemens SIMATIC

CISA's summary

Summary: SIMATIC S7-1500 devices contain a vulnerability that could allow an attacker to inject code by tricking a legitimate user into importing a specially crafted trace file in the web interface. Siemens has released new versions for several affected products and recommends to update to the latest versions. Siemens is preparing further 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-2025-40943 — CVE-2025-40943 · CWE-95

  Affected devices do not properly sanitize contents of trace files. This could allow an attacker to inject code through social engineering an authorized user, who has the function right "Read diagnostics", to import a specially crafted trace file. The malicious trace file is insufficiently sanitized and malicious code could be executed in the clients browser session and trigger PLC operations via the webserver that the legitimate user is authorized to perform.

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.