CVE-2026-67861 is a vulnerability affecting open62541 version 1.5.5 and earlier, an open-source OPC UA implementation. A remote attacker can exploit the UA_Client_getRemoteDataTypes component to cause a denial of service condition. The vulnerability is remotely exploitable without requiring authentication. The issue has been documented on the open62541 GitHub repository. Affected code paths include the client utility functions in ua_client_util.c and related custom datatype handling examples. Given the industrial and IoT context of OPC UA, this vulnerability may affect critical infrastructure environments. Users are advised to review the referenced GitHub issue and update to a patched version when available.