{"uuid": "27f2fee5-a074-4fa6-886d-b53c679d6168", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2026-51535", "type": "seen", "source": "https://gist.github.com/MrAlaskan/bec306c51fec9f777b2599f5dea09dd1", "content": "# Security Advisory: CVE-2026-51535\n\n## Vulnerability Information\n* **CVE ID:** CVE-2026-51535\n* **Vendor:** EIPStackGroup\n* **Product:** OpENer (Version 2.3.0, commit 76b95cf)\n* **Vulnerability Type:** CWE-400: Uncontrolled Resource Consumption\n* **Attack Type:** Remote, Unauthenticated\n* **Impact:** Denial of Service (DoS)\n\n## Description\nA resource exhaustion (Denial of Service) vulnerability exists in the network processing loop of OpENer 2.3.0. \n\n## Affected Component\nThe TCP Network Handler in `source/src/ports/generic_networkhandler.c`, specifically the `HandleDataOnTcpSocket`, `CheckAndHandleTcpListenerSocket`, and `NetworkHandlerProcessCyclic` functions.\n\n## Attack Vectors\nAn unauthenticated, remote attacker with network access to the target slave can exploit this vulnerability by establishing a single TCP connection to the OpENer ENIP port (default TCP/44818) and sending a specially crafted, incomplete Ethernet/IP (ENIP) packet header. By intentionally withholding the remainder of the payload while keeping the connection open (a Slowloris-style attack), the attacker exploits the lack of non-blocking socket configurations to force the server's single-threaded network handler into an indefinite blocking state. This completely stalls the main event loop, resulting in a Denial of Service (DoS) that prevents the device from processing any other legitimate communications.\n\n## References\n* GitHub Issue: https://github.com/EIPStackGroup/OpENer/issues/562", "creation_timestamp": "2026-07-03T06:42:29.534324Z"}