CVE-2026-51537

CRITICAL

EIPStackGroup OpENer 2.3.0 - Unauthenticated Out-of-Bounds Read via Malformed CIP ForwardOpen Request

Title source: llm

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.

References (2)

Core 2

Core References

https://github.com/EIPStackGroup/OpENer/issues/564

https://gist.github.com/MrAlaskan/a5fb0fb7765c9df80d28220ed558f04e

Scores

CVSS v3 9.1

EPSS 0.0044

EPSS Percentile 36.5%

Attack Vector NETWORK

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

CISA SSVC

Vulnrichment

Exploitation poc

Automatable yes

Technical Impact total

Details

CWE

CWE-125

Status published

Published Jul 13, 2026

Tracked Since Jul 14, 2026