Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessReach OpENer device on CIP network
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ExploitSend crafted unconnected explicit message
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ExecutionTrigger out-of-bounds read in message router
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ImpactCrash stack and deny service
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V2 - Validation and Business Logic Resource consumption limits
MITRE ATT&CK
1 technique across 1 tactic: Impact The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Requires network reachability to a device running the OpENer EtherNet/IP adapter stack (v2.3.0 / commit 76b95cf) with its CIP services exposed and processing unconnected explicit messages (typically EtherNet/IP encapsulation over TCP/UDP port 44818). EtherNet/IP has no built-in authentication, so per the CVSS vector exploitation is remote and unauthenticated (PR:N) with no user interaction (UI:N) against the default message-router handling. The main limiting factors are exposure of the device's CIP port to the attacker (industrial networks are often segmented/air-gapped) and the fact that impact is confined to availability - a process crash/DoS, not data disclosure or code execution. |
| Impact | Signals are moderately consistent and point to a genuine but bounded availability risk. The provided CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, base 7.5) indicates a network-reachable, low-complexity, unauthenticated flaw with no user interaction, whose sole impact is high availability loss - consistent with the description of an out-of-bounds read causing denial of service in the unconnected explicit messaging path. There is no confidentiality or integrity impact (C:N/I:N), so this is a crash/DoS primitive, not code execution, despite the 'Buffer Overflow' tag which overstates the nature of an OOB read. No KEV listing and no EPSS score were provided, so real-world exploitation probability cannot be quantified from the input; absence of EPSS/KEV data is a gap, not evidence of low risk. A GitHub issue (#569) is referenced and likely documents the crash condition, but no explicit public exploit code is confirmed in the input, so this should be treated as a reported memory-safety defect rather than a weaponized threat. Net: a legitimate, easy-to-trigger DoS against exposed OpENer-based industrial devices, but impact is limited to availability and the product's deployment footprint is niche (OT/ICS), so it is a priority primarily for operators of EtherNet/IP devices built on this stack rather than a broad internet-wide emergency. |
| Exploit ScenarioDerived | An attacker with network access to an EtherNet/IP device running OpENer sends a crafted unconnected explicit CIP message to the device's message router. Malformed length or offset fields cause an out-of-bounds read while parsing, crashing the OpENer process and taking the industrial device offline. No authentication or user interaction is required; a public proof-of-concept exploit is not confirmed in the provided data, though GitHub issue #569 appears to document the triggering condition. |
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Alert meAnalysisAIv1 – Oct 09, 2026
Remote denial of service against devices running the OpENer EtherNet/IP adapter stack v2.3.0 (commit 76b95cf): an out-of-bounds read in the unconnected explicit messaging path lets a remote, unauthenticated attacker crash or destabilize the CIP stack by sending crafted unconnected explicit requests to an exposed EtherNet/IP interface. The assessed vector (CVSS:3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, score 7.5) confirms network-reachable, unauthenticated exploitation with high availability impact and no confidentiality or integrity impact, so the outcome is a process crash/denial of service rather than data disclosure or code execution. No public exploit code and no confirmed active exploitation were identified at time of analysis, and the practical limiter is whether the device's CIP/encapsulation port (typically TCP/UDP 44818) is reachable across network segmentation.
RemediationAI
Patch status at time of analysis: no vendor-released patch identified - the references point to the upstream GitHub issue https://github.com/EIPStackGroup/OpENer/issues/569 and to the vulnerable commit tree rather than to a tagged fixed release, so integrators should track issue 569 for an upstream fix and, once available, rebuild against the fixed commit and reflash affected devices; because OpENer is typically vendored into OEM firmware, the vendor of the end product (not the upstream project) is the party that must ship the update. Until a fix is confirmed, compensating controls should be applied in this order: restrict reachability of TCP/UDP 44818 to trusted engineering hosts and OT zones via firewall or ACL rules on the cell/zone boundary (trade-off: blocks legitimate HMI, SCADA and configuration traffic unless the trusted host list is maintained), and place OpENer-based devices on a segmented industrial network with no routed path to IT or untrusted networks (trade-off: limits remote diagnostics and requires jump hosts). Where the device profile permits it, disable or reduce unconnected explicit messaging by enforcing connected (class-3) sessions only and closing the port to connectionless requests (trade-off: breaks EDS-based discovery, device configuration and some third-party CIP clients), and enable watchdog-driven automatic restart with alerting on the device so a successful crash is detected and recovers quickly (trade-off: restart cycles disrupt the controlled process). Detection can be complemented with OT IDS/IPS signatures for malformed unconnected explicit CIP requests and monitoring for unexpected process restarts on the adapter, but these are detection-only and must not be treated as a fix.
Affected VersionsENISA
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Technical ContextAI · show details
OpENer is an open-source EtherNet/IP (CIP) adapter/device stack maintained by the EIPStackGroup and widely embedded in industrial controllers, I/O adapters and protocol gateways. The affected code path is unconnected explicit messaging, the UCMM-style request handling implemented in source/src/cip/cipmessagerouter.c, which parses and routes connectionless explicit CIP requests arriving over the EtherNet/IP encapsulation layer (TCP/UDP 44818) before any connected class-3 session exists. Supporting functions named in the references - source/src/cip/cipcommon.c (shared CIP service/EPATH parsing helpers), source/src/cip/ciptcpipinterface.c (the CIP TCP/IP Interface object, class 0x05, used for network configuration queries) and source/src/enet_encap/endianconv.c (little/big-endian conversion of CIP data items) - indicate the failure occurs while decoding attacker-supplied length, offset or item-count fields without sufficient bounds validation, producing a read past the end of a buffer that terminates the process. The provided CWE field is empty, but the supplied tags classify this as a buffer overflow / denial of service, and the described behavior is consistent with an out-of-bounds read (CWE-125) in message parsing rather than a write primitive, which is also why the impact is confined to availability. EtherNet/IP carries no native authentication or integrity protection, which is why the assessed vector is PR:N/UI:N despite the absence of credentials.
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EtherNet/IP is network-reachable and unauthenticated (AV:N/PR:N) with a simple malformed message (AC:L/UI:N); an OOB read yields only a crash, so C:N/I:N/A:H.
Primary rating from Vendor (mitre).
CVSS VectorVendor: mitre
DescriptionCVE.org
OpENer v2.3.0 / commit 76b95cf contains an out-of-bounds read in the unconnected explicit messaging path. This allows a remote attacker to cause a denial of service.
Executive ViewAI
Devices built on the OpENer EtherNet/IP adapter stack v2.3.0 (commit 76b95cf) can be crashed or destabilized remotely by any host able to reach an exposed EtherNet/IP interface, with no credentials required, producing a loss of availability rather than data theft or code execution. Because no vendor patch has been released and the attack surface is simply network reachability to the CIP/encapsulation port (typically TCP/UDP 44818), the practical risk is unplanned downtime or degraded process control wherever these devices are not properly segmented. Leadership should care because the exposure is governed by network architecture decisions already under the organization's control, and industrial, building-automation, or lab environments running this stack may face operational disruption until a fix ships.
No vendor-released patch identified at time of analysis. Interim mitigations: block or tightly restrict TCP/UDP 44818 at perimeter and inter-zone firewalls, permit CIP access only from dedicated trusted engineering hosts, segment EtherNet/IP devices into isolated OT zones per IEC 62443 conduit design, disable or restrict unconnected explicit messaging where the device configuration allows, deploy network monitoring/IDS for malformed CIP explicit requests, and prepare watchdog or automatic-restart procedures to shorten downtime from a stack crash.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
EUVD-2026-95903
GHSA-4pjq-xq9p-gvj5
NVD
CVE.org
EPSS
Exploit-DB