CVE-2026-54156: Node-Opcua

High severity, CVSS 7.5. EPSS: 0.8% chance of exploitation in the next 30 days.

node-opcua is an OPC UA implementation for TypeScript and Node.js. Prior to 2.166.0, the process-global g_alreadyUsedNonce cache used by nonceAlreadyBeenUsed in packages/node-opcua-secure-channel/source/server/server_secure_channel_layer.ts records nonces from OpenSecureChannelRequest and CreateSession without expiration or a size limit. An unauthenticated remote attacker can repeatedly create sessions with unique nonces, causing entries to persist after session expiry and accumulate across connection cycles even when maxSessions=10 limits concurrent sessions. The resulting unbounded heap growth can exhaust the default Node.js heap and crash the node-opcua server process. This issue is fixed in version 2.166.0.

Affected products

• Node-Opcua Node-Opcua: before 2.166.0 (fixed in 2.166.0)

Published 2026-09-14. Last modified 2026-09-30.