How severe is CVE-2026-6899?

CVE-2026-6899 has a CVSS 3.x base score of 5.6, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-6899 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-6899?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-6899 have an EU (EUVD) identifier?

Yes. CVE-2026-6899 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35380.

When was CVE-2026-6899 published?

CVE-2026-6899 was published on 2026-06-09 and last updated on 2026-06-17.

CVE-2026-6899

CVE-2026-6899 is a medium-severity vulnerability with a CVSS 3.x base score of 5.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-299.

Key facts

Severity: Medium (CVSS 3.x base score 5.6)
EPSS exploit prediction: 0% (1st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-35380
Weakness: CWE-299
Published: 2026-06-09
Last modified: 2026-06-17

Description

Check for certificate revocation only considers the first matching CRL and ignores other valid CRLs of the same CA in the CycloneCrypto cryptographic wrapper of S2OPC library. It might allow connection between an OPC UA client and server using a revoked certificate.

Frequently asked questions

What is CVE-2026-6899?: Check for certificate revocation only considers the first matching CRL and ignores other valid CRLs of the same CA in the CycloneCrypto cryptographic wrapper of S2OPC library. It might allow connection between an OPC UA client and server using a revoked certificate.
How severe is CVE-2026-6899?: CVE-2026-6899 has a CVSS 3.x base score of 5.6, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-6899 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-6899?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-6899 have an EU (EUVD) identifier?: Yes. CVE-2026-6899 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35380.
When was CVE-2026-6899 published?: CVE-2026-6899 was published on 2026-06-09 and last updated on 2026-06-17.

References

https://gitlab.com/systerel/S2OPC/-/work_items/1739

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