CVE-2026-54155Public exploitNetwork attack vectorHinoki check available

Authentication bypass via missing session nonce verification

Published Sep 14, 2026 · Updated Sep 14, 2026

Authentication bypass in Sterfive SAS node-opcua 2.165.0 and earlier allows remote attackers to assume accounts via forged or replayed tokens. The UserNameIdentityToken handler decrypts the RSA-OAEP password blob, trusts its little-endian length, and never compares the trailing bytes with the current session serverNonce. Forgery compromises accounts configured to accept an empty password; replay requires captured ciphertext, while SecurityMode=None removes the separate client-signature safeguard.

CVSS severity7.7
High
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Authentication bypass in Sterfive SAS node-opcua 2.165.0 and earlier allows remote attackers to assume accounts via forged or replayed tokens. The UserNameIdentityToken handler decrypts the RSA-OAEP password blob, trusts its little-endian length, and never compares the trailing bytes with the current session serverNonce. Forgery compromises accounts configured to accept an empty password; replay requires captured ciphertext, while SecurityMode=None removes the separate client-signature safeguard.

The record

CVE
CVE-2026-54155
Published
Sep 14, 2026
Updated
Sep 14, 2026
Vendor
Sterfive SAS
Product
node-opcua
Classifications
CWE-347, T1078
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.166.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Sterfive SAS · node-opcuaversion=< 2.166.0

Published CVSS scores

7.7GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1078Valid Accounts

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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