# Siemens OpenSSL flaw impacts 100+ industrial products

Published: 2025-09-16 · Severity: elevated · Sectors: manufacturing, infrastructure
Canonical: https://vorant.io/reports/eb06717f-4764-52ed-9f67-a370dfb9678c/siemens-openssl-flaw-impacts-100-industrial-products

> Out-of-bounds read in OpenSSL (CVE-2021-3712) affecting Siemens SCALANCE, RUGGEDCOM, SIMATIC and other industrial equipment enables remote code execution or denial of service.

A remotely exploitable out-of-bounds read vulnerability in OpenSSL (CVE-2021-3712) affects over 100 Siemens industrial products across multiple product lines. The flaw exists in OpenSSL's handling of ASN.1 strings that lack proper null termination; applications that construct ASN1_STRING structures directly without null-terminating the data field can trigger a buffer overrun when those structures are processed by OpenSSL printing functions or certificate name constraint processing. Successful exploitation allows an unauthenticated remote attacker to achieve arbitrary code execution or denial of service, with potential disclosure of sensitive memory contents including private keys. The vulnerability is present in OpenSSL versions 1.0.2 through 1.0.2y and 1.1.1 through 1.1.1k. Affected Siemens products span industrial networking equipment (SCALANCE switches and wireless devices), ruggedized networking devices (RUGGEDCOM), automation controllers (SIMATIC), and industrial software platforms (SINEMA, SINUMERIK, PCS neo). Mitigation requires updating to patched versions; several products have no fix currently planned and users should contact Siemens support. The advisory does not indicate active in-the-wild exploitation, but the remote exploitability and impact warrant prompt patching of exposed systems.

## Mentioned in this report

- Vulnerabilities: CVE-2021-3712

Source reporting: https://www.cisa.gov/news-events/ics-advisories/icsa-25-259-05

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