What’s Vulnerable › Vulnerabilities
CVE-2026-6899: Improper Check for Certificate Revocation in S2OPC
- Severity: medium (CVSS 5.6 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.1% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-06-09 · updated 2026-07-23
- Weakness: CWE-299
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.
Affected products
- Systerel S2OPC: from 1.5.0 before 1.7.3 — fixed in 1.7.3
How to fix
Upgrade to a fixed version: Systerel S2OPC 1.7.3. Check the vendor advisory for mitigations.
References
Get alerted when CVE-2026-6899 or the next vulnerability affects your stack