The AddNodes service in Systerel S2OPC allows manipulation of the UserAccessLevel parameter to trigger an out‑of‑bounds read in the SOPC_NodeMgtHelperInternal_AddVariableNodeAttributes function. This flaw is capable of leaking memory contents beyond the expected buffer, providing a pathway for information disclosure when exploited remotely. While the current exploit requires significant complexity and is difficult to execute, the vulnerability has been publicly disclosed and could be leveraged by determined attackers.

Systerel S2OPC versions up to 1.7.3 are affected. The vulnerability resides in the src/ClientServer/address_space/internal/sopc_node_mgt_helper_internal.c file of the AddNodes Service component. All builds based on those releases without the identified patch are susceptible.

The CVSS v3.1 score of 6.3 indicates moderate severity, and the lack of an EPSS rating means current data does not quantify exploitation probability. The flaw is not yet listed in CISA's KEV catalog. Attackers would need remote access to the AddNodes endpoint and considerable expertise to craft a payload that triggers the out‑of‑bounds read, yet the publicly disclosed nature of the vulnerability increases the risk of future exploitation. Systems exposed to untrusted inputs should consider immediate mitigation.