dbcve.org
Ua .netstandardApplication · Opcfoundation

CVE-2023-31048

MEDIUM · 5.3 CVSS v3.1 Published 2023-12-12
Fix available
A fix is available. Upgrade to 1.4.371.86 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The OPC UA .NET Standard Reference Server before 1.4.371.86. places sensitive information into an error message that may be seen remotely.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

This is an information disclosure vulnerability in the OPC UA .NET Standard Reference Server versions prior to 1.4.371.86. The server improperly includes sensitive information (such as system paths, configuration details, or stack traces) in error messages that are returned to remote clients, allowing attackers to gather reconnaissance information.

MitigationUpgrade the OPC UA .NET Standard Reference Server to version 1.4.371.86 or later, which addresses the improper error message handling. If upgrading is not immediately possible, review and sanitize error handling routines to ensure sensitive data is not exposed in client-facing messages.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Ua .netstandardApplication
Affected:< 1.4.371.86

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed version of OPC UA .NET Standard Reference Server
    Check the version of the Opcfoundation.Ua.ReferenceServer package or executable. In .NET applications, this can be found in the project file (PackageReferences), the deployed binaries, or by inspecting the assembly version of the reference server executable if already installed.
    Affected if The installed version is lower than 1.4.371.86 (e.g., 1.4.x.y where y < 86, or any earlier major version).
  2. Confirm server is running and network-accessible
    Verify that the OPC UA Reference Server is currently running and listening on its configured endpoint (typically opc.tcp://<hostname>:4840). Use netstat or a network scanner to confirm the port is open and accepting connections.
    Affected if The server is accessible over the network to remote clients, which is required for them to receive the sensitive error messages.
  3. Check if server exposes error details to remote clients
    Connect to the server endpoint using an OPC UA client (such as a minimal test client) and trigger an intentional error condition (e.g., request a non-existent node, use invalid credentials, or cause a fault by sending malformed data). Inspect the returned error response for sensitive information such as file paths, internal configuration values, stack traces, or server environment details.
    Affected if The error response returned to the client contains system file paths, configuration details, stack traces, or other internal server information that should not be exposed to remote clients.

A user is affected if the OPC UA .NET Standard Reference Server version is below 1.4.371.86 AND the server is accessible to remote clients, who could receive sensitive information in error responses.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.4.371.86 or later
Fixed in 1.4.371.86
Interim mitigation

Upgrade the OPC UA .NET Standard Reference Server to version 1.4.371.86 or later, which addresses the improper error message handling. If upgrading is not immediately possible, review and sanitize error handling routines to ensure sensitive data is not exposed in client-facing messages.

Recommended fix High confidence

1.4.371.86 or later

  1. 1. Identify all instances of OPC UA .NET Standard Reference Server running version earlier than 1.4.371.86
  2. 2. Download the fixed version (1.4.371.86 or later) from the official OPC Foundation repository at files.opcfoundation.org or github.com
  3. 3. Backup current server configuration and any custom applications integrated with the reference server
  4. 4. Stop the running OPC UA .NET Standard Reference Server service
  5. 5. Install or deploy the updated version 1.4.371.86 or later
  6. 6. Restore the server configuration from the backup if needed
  7. 7. Restart the OPC UA .NET Standard Reference Server service
  8. 8. Verify the server is running without errors and that error messages no longer expose sensitive information

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Ua .netstandard Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-31048 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data