ICSA-21-315-03: Siemens SIMATIC WinCC (Update E)

CISA's summary

Summary: Multiple vulnerabilities were found in SIMATIC WinCC that ultimately could allow local or remote attackers to escalate privileges and read, write or delete critical files. Siemens has released updates for several affected products and recommends to update to the latest versions. Siemens recommends specific countermeasures for products where updates are not, or not yet available. Note: The vulnerability CVE-2021-40359 is part of a shared component, used by various Siemens products (SIMATIC Communication Services - SCS). The installation of a fix version of any product also removes the vulnerability for other products on the same system, even if those products were not updated.

Products, as the advisory lists them

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

Vulnerabilities in this advisory

• CVE-2021-40358 — CVE-2021-40358 · CWE-22

  Legitimate file operations on the web server of the affected systems do not properly neutralize special elements within the pathname. An attacker could then cause the pathname to resolve to a location outside of the restricted directory on the server and read, write or delete unexpected critical files.

• CVE-2021-40359 — CVE-2021-40359 · CWE-22

  When downloading files, the affected systems do not properly neutralize special elements within the pathname. An attacker could then cause the pathname to resolve to a location outside of the restricted directory on the server and read unexpected critical files.

• CVE-2021-40364 — CVE-2021-40364 · CWE-532

  The affected systems store sensitive information in log files. An attacker with access to the log files could publicly expose the information or reuse it to develop further attacks on the system.

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.