CVE-2026-9758
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 · uneditedImproper comparison with the certificates trusted list in S2OPC allows an attacker well-formed untrusted certificate to be considered trusted
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 confidenceIn S2OPC (an OPC UA stack implementation), the certificate validation logic performs an improper comparison when checking certificates against the trusted certificate list. This allows a well-formed but untrusted certificate to be incorrectly accepted as trusted, bypassing the intended certificate trust model.
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
- Low
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
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 checksWork through these to decide whether this CVE applies to you.
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Identify S2OPC installationLocate the S2OPC library files (typically named libs2opc_*.so, libs2opc_clientserver.so, or s2opc.dll) in your environment. Check application dependencies or container images for references to S2OPC or OPC UA stack libraries.Affected if S2OPC library is present in the environment
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Determine S2OPC versionRun 'strings' on the library file and search for version strings, or check the application's build manifest, library metadata, or release notes for the S2OPC version number.Affected if Version cannot be verified or is not the latest patched release
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Verify certificate validation is in useInspect the S2OPC configuration files (typically XML or JSON configuration) for the 'CertificateValidationMode' setting or similar trust validation configuration. Look for references to 'TrustedCertificateStore' or 'TrustList' in the configuration.Affected if Certificate validation is enabled and trust list is configured
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Inspect trust validation configurationExamine the trust validation configuration files for the certificate validation mode. Check if 'TrustOnFirstUse', 'CertificateChain', or similar certificate acceptance settings are defined. Review logs for certificate validation events.Affected if Certificate trust validation is configured to accept certificates from a trust list or store
If S2OPC is present with certificate validation enabled and a configured trust list, the improper certificate comparison flaw may cause untrusted certificates to be incorrectly accepted.
Generated from the published advisory. Verify against your own configuration.
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 dataFix the certificate comparison logic in the S2OPC trust validation routine to properly verify certificate identity against the trusted list, ensuring only certificates from the trusted store are accepted.
- Consultation6.0 h
- Implementation12.0 h
- Testing10.0 h
- Review / QA6.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $9,504.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-9758 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-9758 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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