EIPStackGroup OpENer 2.3.0 (commit 76b95cf) suffers from an Incorrect Access Control vulnerability in its handling of encapsulation sessions. When the server processes critical encapsulation commands, it verifies whether the provided session_handle exists in the global session list, but it fails to verify whether that handle belongs to the specific TCP connection issuing the request. Because there is no strong binding between a session handle and its originating socket, any attacker on the network can use a valid session handle created by another legitimate client to bypass access controls.
CVE-2026-51538
CRITICALPre-NVD 9.1Trending — 4 sources updated this weekElevated
9.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.1Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 9.1
- EG Score
- 0.0(none)
- EPSS
- 30.1%
- KEV
- Not listed
Published
July 13, 2026
Last Modified
July 15, 2026
Advisory Details (2)
Auto-updated Jul 14, 2026No patch confirmed yet.
generic
Incorrect Access Control on Session Handles · Issue #565 · EIPStackGroup/OpENer · GitHub
https://github.com/EIPStackGroup/OpENer/issues/565Vendor Advisories for CVE-2026-51538(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 8× in last 7d / 8× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-14 13:45 UTCMITRE cvelistV5CVSS v3 → 9.1 · severity → CRITICAL
- 2026-07-13 22:28 UTCNVD update
- 2026-07-13 21:44 UTCEG score recompute
- 2026-07-13 21:42 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Same CWE
10 shownCWE-284
Frequently asked(5)
What is CVE-2026-51538?
CVE-2026-51538 is a critical vulnerability published on July 13, 2026. EIPStackGroup OpENer 2.3.0 (commit 76b95cf) suffers from an Incorrect Access Control vulnerability in its handling of encapsulation sessions. When the server processes critical encapsulation commands, it verifies whether the provided session_handle exists in the global session list, but it fails to…
When was CVE-2026-51538 disclosed?
CVE-2026-51538 was first published in the National Vulnerability Database on July 13, 2026, with the most recent update on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-51538 actively exploited?
CVE-2026-51538 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 30.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-51538?
CVE-2026-51538 has a CVSS v3.1 base score of 9.1 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 0.0.
How do I remediate CVE-2026-51538?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-51538, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-51538
Is Your Infrastructure Affected by CVE-2026-51538?
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