ICSA-21-103-07: Siemens Web Server of SCALANCE X200 (Update A)

CISA's summary

Summary: Several SCALANCE X-200 switches contain buffer overflow vulnerabilities in the web server. In the most severe case an attacker could potentially remotely execute code. Siemens is preparing updates and recommends specific countermeasures for products where updates 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-2021-25668 — CVE-2021-25668 · CWE-122

  Incorrect processing of POST requests in the webserver may result in write out of bounds in heap. An attacker might leverage this to cause denial-of-service on the device and potentially remotely execute code.

• CVE-2021-25669 — CVE-2021-25669 · CWE-121

  Incorrect processing of POST requests in the web server may write out of bounds in stack. An attacker might leverage this to denial-of-service of the device or remote code execution.

Acknowledgments, as the advisory lists them

• Siemens ProductCERT: reporting these vulnerabilities to CISA.

The advisory's legal notice

Siemens Security Advisories are subject to the terms and conditions contained in Siemens' underlying license terms or other applicable agreements previously agreed to with Siemens (hereinafter "License Terms"). To the extent applicable to information, software or documentation made available in or through a Siemens Security Advisory, the Terms of Use of Siemens' Global Website (https://www.siemens.com/terms_of_use, hereinafter "Terms of Use"), in particular Sections 8-10 of the Terms of Use, shall apply additionally. In case of conflicts, the License Terms shall prevail over the Terms of Use.

Sources

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

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