CVE-2026-51537 — CRITICAL (9.1)

Vulnerability Description

EIPStackGroup OpENer 2.3.0 (commit 76b95cf) has an out-of-bounds read issue in Connection Manager handling of ForwardOpen requests when processing short malformed packets. An attacker can send a valid ENIP outer frame carrying a malformed CIP ForwardOpen/LargeForwardOpen request, causing the parser to continue reading fields even when request data is insufficient. This issue is remotely triggerable via network traffic and does not require authentication.

CVSS Score

9.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

NONE

Availability

HIGH

Affected Products

Vendor	Product	Versions
Opener Project	Opener	2.3.0

Related Weaknesses (CWE)

CWE-125

References

https://gist.github.com/MrAlaskan/a5fb0fb7765c9df80d28220ed558f04eThird Party Advisory
https://github.com/EIPStackGroup/OpENer/issues/564ExploitIssue TrackingVendor Advisory
https://github.com/EIPStackGroup/OpENer/issues/564ExploitIssue TrackingVendor Advisory

FAQ

What is CVE-2026-51537?

CVE-2026-51537 is a vulnerability with a CVSS score of 9.1 (CRITICAL). EIPStackGroup OpENer 2.3.0 (commit 76b95cf) has an out-of-bounds read issue in Connection Manager handling of ForwardOpen requests when processing short malformed packets. An attacker can send a valid...

How severe is CVE-2026-51537?

CVE-2026-51537 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2026-51537?

Check the references section above for vendor advisories and patch information. Affected products include: Opener Project Opener.