ICSA-21-257-15: Siemens SIMATIC NET CP Modules
CISA advisory · released 2021-09-14
Source record Collected from CISA's CSAF advisory feed
- Distribution label in the document: TLP:WHITE
- Revision 5, 2025-05-06 (final)
CISA's summary
Summary: A denial of service vulnerability was identified in different types of Communication Processors. An attacker could exploit this vulnerability causing the device to become un-operational until the device is restarted. 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.
Products, as the advisory lists them
| Vendor | Product | Version |
|---|---|---|
| Siemens | SIMATIC CP 343-1 (incl. SIPLUS variants) | vers:all/* |
| Siemens | SIMATIC CP 343-1 Advanced (incl. SIPLUS variants) | vers:all/* |
| Siemens | SIMATIC CP 343-1 ERPC (6GK7343-1FX00-0XE0) | vers:all/* |
| Siemens | SIMATIC CP 343-1 Lean (incl. SIPLUS variants) | vers:all/* |
| Siemens | SIMATIC CP 443-1 (6GK7443-1EX30-0XE0) | <V3.3 |
| Siemens | SIMATIC CP 443-1 (6GK7443-1EX30-0XE1) | <V3.3 |
| Siemens | SIMATIC CP 443-1 Advanced (6GK7443-1GX30-0XE0) | <V3.3 |
| Siemens | SIPLUS NET CP 443-1 (6AG1443-1EX30-4XE0) | <V3.3 |
| Siemens | SIPLUS NET CP 443-1 Advanced (6AG1443-1GX30-4XE0) | <V3.3 |
DeSpy has not checked any unit, hardware revision or firmware.
Vulnerabilities in this advisory
- CVE-2021-33737 — CVE-2021-33737 · CWE-119
Sending a specially crafted packet to port 102/tcp of an affected device could cause a denial of service condition. A restart is needed to restore normal operations.
Acknowledgments, as the advisory lists them
- Siemens ProductCERT: reporting this vulnerability 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
DeSpy's copy of this version is dated 2026-09-28.
This product uses the NVD API but is not endorsed or certified by the NVD.
CVE records: Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.
CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.
CISA's Known Exploited Vulnerabilities catalog and CISA Vulnrichment data are CC0 1.0. CISA advisories are shown with the TLP label their document carries. No endorsement by CISA, DHS, NIST or MITRE is stated or implied.