CVE-2026-67871 in S2OPC
Summary
by MITRE • 08/06/2026
Buffer Overflow vulnerability in Systerel S2OPC 1.7.3 allows a remote attacker to cause a denial of service via the AddNodes, address_space_bs.c, sopc_node_mgt_helper_internal.c, and toolkit_test_server
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Analysis
by VulDB Data Team • 08/06/2026
The buffer overflow vulnerability in Systerel S2OPC 1.7.3 represents a critical security flaw that enables remote attackers to execute denial of service attacks against industrial automation systems. This vulnerability specifically affects the AddNodes functionality within the OPC UA communication stack, creating a pathway for malicious actors to disrupt normal operations through carefully crafted malformed requests. The flaw manifests in multiple components including address_space_bs.c and sopc_node_mgt_helper_internal.c, indicating a systemic issue within the software's node management and address space handling mechanisms.
The technical implementation of this vulnerability stems from inadequate input validation and memory management practices within the S2OPC toolkit's core modules. When processing AddNodes requests, the software fails to properly bounds-check incoming data structures, allowing attackers to overflow allocated buffers and potentially overwrite adjacent memory regions. This type of vulnerability maps directly to CWE-121, which describes buffer overflow conditions in stack-based buffers, and CWE-787, which addresses out-of-bounds write vulnerabilities. The attack surface is particularly concerning given that OPC UA servers are commonly deployed in industrial control systems where reliability and availability are paramount.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise entire industrial control networks. Remote attackers can exploit this flaw to crash the S2OPC server instance, causing cascading failures in connected systems that depend on OPC UA communication for process control and monitoring. The toolkit_test_server component adds additional risk as it may be exposed in development or testing environments, providing attackers with additional attack vectors. This vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and potentially T1566.002 for initial access through network services.
Organizations utilizing Systerel S2OPC 1.7.3 should implement immediate mitigations including network segmentation to limit access to OPC UA ports, deployment of intrusion detection systems to monitor for suspicious AddNodes activity, and implementation of input validation controls at network boundaries. The most effective long-term solution involves upgrading to patched versions of the S2OPC toolkit where memory safety mechanisms have been properly implemented. Security teams should also conduct comprehensive vulnerability assessments of their industrial control networks to identify other potentially affected systems that may be running vulnerable versions of OPC UA implementations, as these vulnerabilities often propagate across similar software ecosystems in industrial environments.