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Improper Certificate ValidationWeakness · CWE-295

CVE-2025-7390

CRITICAL · 9.1 CVSS v3.1 Published 2025-08-21
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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
A malicious client can bypass the client certificate trust check of an opc.https server when the server endpoint is configured to allow only secure communication.

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 vulnerability exists in OPC (Open Platform Communications) HTTPS servers where client certificate trust validation can be bypassed. When the server endpoint is configured to enforce secure communication, a malicious client can successfully connect without proper certificate verification, effectively negating the mutual TLS authentication intended to ensure only trusted clients can access the server.

MitigationOrganizations should verify that proper certificate chain validation is being performed in the OPC server configuration and consider additional network-level controls until the vendor patch is available. Review and restrict which certificate authorities are trusted for client authentication.

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

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
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 OPC server installation and version
    Locate the OPC UA server application and its configuration files; common locations include installation directories, config folders, or application data directories. Check the application version against any available release notes or vendor documentation.
    Affected if OPC UA HTTPS server is present and version is within the affected range if provided by vendor.
  2. Verify HTTPS secure communication is enabled
    Inspect the OPC server endpoint configuration to confirm the server is configured to use HTTPS or secure transport (look for security policies such as Basic128Rsa15, Basic256, or Aes256_Sha256_RsaPss in the endpoint settings).
    Affected if Server endpoints are configured to enforce secure communication via HTTPS.
  3. Inspect client certificate validation settings
    Review the OPC server configuration files for certificate validation parameters such as 'AutoAccept', 'TrustList', 'TrustedCertificateAuthorities', or 'ValidateCertificate' settings that control how client certificates are verified.
    Affected if Certificate validation is configured to allow connections without proper trust chain verification.
  4. Check trust validation bypass configuration
    Look for settings that disable or weaken certificate trust validation, such as flags allowing unauthenticated clients, skipping certificate chain validation, or accepting self-signed certificates without proper trust verification.
    Affected if Trust validation is disabled, set to accept all certificates, or configured to bypass chain validation.
  5. Review endpoint security policy configuration
    Examine the server endpoint security policies and ensure they require Certificate validation type (e.g., Certificate_sha256 or Certificate) rather than None or Anonymous for client authentication.
    Affected if Endpoint security policy does not enforce proper client certificate authentication.

The environment is affected if an OPC HTTPS server is running with client certificate trust validation disabled or bypassed in its configuration.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Organizations should verify that proper certificate chain validation is being performed in the OPC server configuration and consider additional network-level controls until the vendor patch is available. Review and restrict which certificate authorities are trusted for client authentication.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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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-2025-7390 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
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