Vulnerability in Opener Project
CVE-2026-51538
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.005 (42.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 42.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.001
Affected products
- Opener Project — versions 2.3.0
Weakness classification (CWE)
References
- github.com/EIPStackGroup/OpENer/issues/565 (Exploit, Issue Tracking, Vendor Advisory)
- gist.github.com/MrAlaskan/8156ca3acd6754a9f66efede0a1351f2 (Third Party Advisory)
Frequently asked questions
- What is CVE-2026-51538?
- CVE-2026-51538 is a critical-severity vulnerability in Opener Project, classified under Improper Access Control. CVSS score: 9.1/10. Published 2026-07-13.
- How severe is CVE-2026-51538?
- Critical severity. CVSS v3 base score is 9.1 out of 10.