CVE-2025-3756

CVE-2025-3756 is a denial-of-service vulnerability in the IEC 61850 communication stack affecting multiple ABB automation products, including AC800M System 800xA, Symphony Plus SD Series, Symphony Plus MR, and S+ Operations. An attacker with network access to IEC 61850 communication interfaces could exploit the vulnerability by sending specially crafted packets to force communication modules (PM 877, CI850, CI868) into fault mode or disable IEC 61850 connectivity. The impact is limited to the 61850 communication function and does not affect the overall availability of the S+ Operations node itself. The vulnerability carries a CVSS 3.1 score of 6.5 (Medium) with an adjacent network attack vector, requiring no authentication or user interaction. The attack has high availability impact but does not compromise confidentiality or integrity. The EPSS score of 0.00025 indicates extremely low probability of exploitation in the wild relative to all known CVEs, suggesting this remains a theoretical concern rather than an active threat in observed attack patterns. The vulnerability shows no signs of active exploitation. It is not listed on the CISA Known Exploited Vulnerabilities catalog and remains inactive on the Hot List, indicating no identified in-the-wild exploitation activity or publicly available exploit code. Community attention appears minimal, consistent with the very low EPSS score and niche applicability to industrial control system environments.