CVE-2026-54156

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.8% (54th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.8%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
49
EG Risk 49/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation1% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.8%
EPSS %ILE
54th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 20, 2026

Last Modified

September 30, 2026

Advisory Details (2)

Auto-updated Sep 14, 2026
Patch available. Sources: github, github_commit.
github_commit

commit b82c2939fe9c (node-opcua/node-opcua)

Fix landed in node-opcua/node-opcua commit b82c2939fe9c — awaiting tagged release

https://github.com/node-opcua/node-opcua/commit/b82c2939fe9c658de58da993f2798ec5481d7313
github Patch Available

[Security] Unbounded nonce cache enables unauthenticated heap exhaustion DoS (CVSS 7.5) · Advisory · node-opcua/node-opcua · GitHub

https://github.com/node-opcua/node-opcua/security/advisories/GHSA-6wvw-vrw4-363w

Vendor Advisories for CVE-2026-54156(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFix by version rangeDependents
node-opcua—
  • every version up to 2.166.0: fixed in 2.166.0
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 15× in last 7d / 37× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-05 05:00 UTCEG score recompute
  2. 2026-10-04 23:22 UTCEPSS rescore
  3. 2026-10-03 17:35 UTCEG score recompute
  4. 2026-10-03 14:26 UTCEPSS rescore
  5. 2026-10-02 19:25 UTCEG score recompute
  6. 2026-10-02 17:56 UTCEPSS rescore
  7. 2026-10-01 21:28 UTCEG score recompute
  8. 2026-10-01 19:50 UTCEPSS rescore
  9. 2026-09-30 19:43 UTCEG score recompute
  10. 2026-09-30 15:03 UTCEPSS rescore
  11. 2026-09-30 08:12 UTCEG score recompute
  12. 2026-09-29 15:22 UTCEPSS rescore
  13. 2026-09-29 01:54 UTCEG score recompute
  14. 2026-09-28 13:55 UTCEG score recompute
  15. 2026-09-28 13:51 UTCEPSS rescore
  16. 2026-09-27 15:55 UTCEG score recompute
  17. 2026-09-27 13:48 UTCEPSS rescore
  18. 2026-09-27 02:58 UTCEG score recompute
  19. 2026-09-26 15:59 UTCEPSS rescore
  20. 2026-09-24 19:06 UTCEG score recompute
  21. 2026-09-24 14:04 UTCEPSS rescore
  22. 2026-09-23 20:03 UTCEG score recompute
  23. 2026-09-23 17:54 UTCEPSS rescore
  24. 2026-09-22 19:45 UTCEG score recompute
  25. 2026-09-22 05:48 UTCEG score recompute
Show 13 more
  1. 2026-09-21 07:49 UTCEG score recompute
  2. 2026-09-20 20:16 UTCEPSS rescore
  3. 2026-09-19 20:02 UTCEG score recompute
  4. 2026-09-18 22:05 UTCEG score recompute
  5. 2026-09-18 19:28 UTCEPSS rescore
  6. 2026-09-18 00:08 UTCEG score recompute
  7. 2026-09-17 19:31 UTCEPSS rescore
  8. 2026-09-16 14:41 UTCEG score recompute
  9. 2026-09-16 14:08 UTCEPSS rescore
  10. 2026-09-16 05:15 UTCEPSS rescore
  11. 2026-09-14 17:55 UTCEG score recompute
  12. 2026-09-14 16:45 UTCEG score recompute
  13. 2026-08-20 18:42 UTCEG score recompute

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-54156?
CVE-2026-54156 is a high vulnerability published on August 20, 2026. node-opcua is an OPC UA implementation for TypeScript and Node.js. Prior to 2.166.0, the process-global galreadyUsedNonce cache used by nonceAlreadyBeenUsed in packages/node-opcua-secure-channel/source/server/serversecurechannellayer.ts records nonces from OpenSecureChannelRequest and CreateSession…
When was CVE-2026-54156 disclosed?
CVE-2026-54156 was first published on August 20, 2026, with the most recent update on September 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-54156 actively exploited?
CVE-2026-54156 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (54th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-54156?
CVE-2026-54156 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-54156?
A fix for CVE-2026-54156 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-54156 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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