CVE-2026-11946
HighCVSS 7.5Summary
An unauthenticated remote attacker can exhaust server memory via the GetEndpoints Discovery Service in open62541. The endpointUrl field of GetEndpointsRequest is not validated for length, allowing an arbitrarily large string (up to ~4.09 GB) to be declared and delivered across intermediate chunks without ever sending the final chunk. The server buffers all chunks in RAM indefinitely until the SecureChannel times out.
Risk Assessment
The attack can lead to server memory exhaustion, causing a denial of service (DoS) and disrupting industrial systems or critical infrastructure. Since the attack is pre-session and bypasses all encryption configurations, it is particularly dangerous for production environments.
Recommendation
Immediately update open62541 to version 1.4.17, 1.5.5, or later, which includes validation of the endpointUrl field length. If an update is not possible, restrict access to the OPC UA server to trusted networks only using a firewall.
Original NVD description (English source)
An unauthenticated remote attacker can exhaust server memory via the GetEndpoints Discovery Service in open62541. The endpointUrl field of GetEndpointsRequest is not validated for length. An attacker can declare an arbitrarily large string (up to ~4.09 GB via the UInt32 length field) delivered across intermediate chunks without ever sending the final chunk. The server buffers all chunks in RAM indefinitely until the SecureChannel times out. The attack is pre-session and bypasses all encryption configurations. The issue affects open62541: from 1.4.0 through 1.4.16, from 1.5.0 through 1.5.4, master.