CVE-2026-18257: Systerel S2OPC · Improper Certificate Validation
Affects Systerel S2OPCSource CVE Database V5
Not known to be exploited · CVSS 5.6 Medium : upgrade to 2.0.0 when convenient.
Data as of 27 Oct 2026, 17:11 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 2.0.0
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:LExploitation evidence
Disclosed: evidence found.
CVE published 29 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade Systerel S2OPC to 2.0.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| SysterelS2OPC | Affected
| Fixed in
|
GitHubsysterel/S2OPCpkg:github/systerel/S2OPCOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, users should consider additional certificate validation controls or restrict trust to known good certificates where possible.
Description
Improper validity period check for root issuer certificate in CycloneCrypto cryptographic wrapper of S2OPC allows a certificate issued by this root issuer to be considered trusted