Answer in brief
CVE-2026-54156 records a High severity (CVSS 7.5) vulnerability in node-opcua: Unbounded nonce cache enables unauthenticated heap exhaustion DoS. The current sources do not mark it as known exploited. The current feed maps node-opcua/node-opcua (generic), node-opcua (npm), node-opcua (npm), node-opcua (npm). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps node-opcua/node-opcua (generic), node-opcua (npm), node-opcua (npm), node-opcua (npm). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| node-opcua/node-opcuageneric | <2.166.0 | 2.166.0 |
| node-opcuanpm | <=2.165.0 | 2.168.0 |
| node-opcuanpm | <2.166.0 | 2.166.0 |
| node-opcuanpm | >=0 <2.166.0 | 2.166.0 |
Published upstream
Sep 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 30, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 20, 2026
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.
Quoted source text, attributed separately from HOL analysis.