CVE-2026-54156: node-opcua Denial of Service Vulnerability
HIGHCVE-2026-54156 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting node-opcua libraries in the npm ecosystem. The issue involves unbounded nonce cache enables unauthenticated heap exhaustion dos. Remediation is available by upgrading affected packages to version 2.166.0.
CVE-2026-54156 at a Glance
Security Impact
CVSS: 7.5
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
How to Fix CVE-2026-54156
To remediate this vulnerability, upgrade all affected node-opcua dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
npm install node-opcua@2.166.0Run the following command in your project directory to verify that all resolved dependencies use the patched release:
npm ls node-opcuaHow to Check if You Are Affected
To determine whether your Node.js application is affected by CVE-2026-54156, inspect your project dependencies using npm:
npm ls node-opcuaAnalyze the terminal output to locate any version of node-opcua in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.166.0), your application is affected.
Note: The npm ls node-opcua command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. In node-opcua, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-54156 Affected node-opcua Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
node-opcua
|
npm |
< 2.166.0
|
2.166.0
|
References
Frequently Asked Questions
What is CVE-2026-54156?
Which node-opcua versions are affected?
What version fixes CVE-2026-54156?
Is node-opcua affected?
What is the CVSS score of CVE-2026-54156?
What CWE is associated with CVE-2026-54156?
How can I check npm dependencies for CVE-2026-54156?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-6wvw-vrw4-363w",
"modified" : "2026-08-27T19:04:40Z",
"published" : "2026-08-20T18:35:41Z",
"aliases" : [ "CVE-2026-54156" ],
"summary" : "node-opcua: Unbounded nonce cache enables unauthenticated heap exhaustion DoS",
"details" : "**Summary**\nA process-global nonce cache with no eviction policy allows an unauthenticated remote attacker to exhaust server heap memory by repeatedly opening sessions, causing the node-opcua server process to crash.\n\n**Affected versions:** <= 2.165.0\n**Tested version:** 2.165.0\n**CVSS Score:** 7.5 (High)\n**CVSS Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\n**CWE:** CWE-770 Allocation of Resources Without Limits or Throttling\n\n---\n\n**Root Cause**\n\nIn `packages/node-opcua-secure-channel/source/server/server_secure_channel_layer.ts` at line 156, `g_alreadyUsedNonce` is a process-global object used to track previously seen nonces for replay detection. Entries are added on every `OpenSecureChannelRequest` and every `CreateSession` request but are never removed or expired.\n\nAn unauthenticated attacker can exploit the `CreateSession` path (which requires no certificate) to accumulate nonce entries indefinitely. Even with `maxSessions=10` limiting concurrent sessions, nonces persist after session expiry, allowing slow but reliable heap exhaustion across repeated connection cycles.\n\n---\n\n**Measured Impact**\n\nDynamically confirmed heap growth:\n- 5,000 unique nonces → +1.23 MB resident heap, no eviction after explicit GC\n- Projected: 10^6 nonces → ~246 MB resident heap\n- Achievable OOM on default Node.js heap limits\n\n---\n\n**Suggested Fix**\n\nAdd a TTL-based eviction policy to `g_alreadyUsedNonce`. Nonces should be expired after the maximum session timeout (or a reasonable fixed window, e.g. 1 hour). A Map with timestamp entries and periodic cleanup is sufficient.\n\n---\n\nI am following a 90-day responsible disclosure policy. I am happy to provide additional technical details under embargo. Please confirm receipt at your earliest convenience.\n\nReporter: Stanley Tobias\nDiscovery date: 2026-03-23",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "npm",
"name" : "node-opcua"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "2.166.0"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/node-opcua/node-opcua/security/advisories/GHSA-6wvw-vrw4-363w"
}, {
"type" : "WEB",
"url" : "https://github.com/node-opcua/node-opcua/commit/b82c2939fe9c658de58da993f2798ec5481d7313"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/node-opcua/node-opcua"
}, {
"type" : "WEB",
"url" : "https://github.com/node-opcua/node-opcua/releases/tag/v2.166.0"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-770" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2026-08-20T18:35:41Z",
"nvd_published_at" : null
}
}