CVE-2026-15690: open62541 Shared Client ua_client_connect.c responseReadNamespacesArray null pointer dereference

A vulnerability was identified in open62541 up to 1.5.5. Affected by this issue is the function responseReadNamespacesArray of the file src/client/uaclientconnect.c of the component Shared Client Library. Such manipulation of the argument ServerNamespaceArray leads to null pointer dereference. The attack can be executed remotely. The attack requires a high level of complexity. The exploitation is known to be difficult. The exploit is publicly available and might be used. The project closed the issue report, stating that this is not the official way to report a security vulnerability.