Home/CVE/EIPStackGroup OpENer 2.3.0 (commit 76b95cf) suffers from an Incorrect Access Control vulnerability in its handling of en
CVE
CVE-2026-51538
EIPStackGroup OpENer 2.3.0 (commit 76b95cf) suffers from an Incorrect Access Control vulnerability in its handling of en
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.
EPSS 0.00198
EPSS exploitation odds0.20% · top 90%
Monitor
- ⚠ NVD has not scored this CVE yet - manual triage required (common for recent CVEs)
Sigma rules0
YARA rules0
Look this up elsewhere - one-click external pivots
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How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2026-51538, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked.
EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal.
CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score.
Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits.
PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
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Severity & exploitation scoring
EPSS exploitation probability
0.20%
Top 90%odds of exploitation in the next 30 days
CVSS metric silhouette
No structured CVSS vector for this CVE. Older entries often have only a numeric base score - the metric breakdown radar requires a full
AV:_/AC:_/... vector string published by NVD.SSVC triage
No SSVC vulnrichment for this CVE. CISA's Vulnrichment program scores newer CVEs (~2024 onwards) plus selected older critical ones. Use the EPSS probability + KEV status to triage instead.
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References & Sources
2Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.