Opengear Console Server index.cgi Heap-based Buffer Overflow Vulnerability (CVE-2026-102212) Technical Advisory

1. Vulnerability Overview & Root Cause

This vulnerability (CVE-2026-102212) is a heap-based buffer overflow (CWE-122) residing within the index.cgi binary of Opengear console servers. The root cause lies in the insufficient boundary validation and length checks when parsing HTTP multipart/form-data POST requests. Specifically, when the index.cgi process processes an overlong name field inside the Content-Disposition header, it copies the data into a heap-allocated buffer without verifying if the input size exceeds the allocated memory space, leading to memory corruption.

2. Exploitation Mechanics & Attack Scenario

An unauthenticated remote attacker can exploit this vulnerability by sending a specially crafted HTTP POST request to the web management interface of the target Opengear appliance. The request payload utilizes the multipart/form-data content type and contains an excessively long string in the name parameter of the Content-Disposition header. When index.cgi attempts to parse this parameter, the heap buffer overflows, overwriting adjacent heap metadata or structures. This initially causes the index.cgi process to crash (Denial of Service). With precise heap layout manipulation, an attacker could hijack the execution flow to achieve remote code execution (RCE) under the context of the web server process.

3. Infrastructure & Business Impact

Opengear console servers are critical infrastructure components used for Out-of-Band (OOB) management of core network devices such as routers, switches, and firewalls. Successful exploitation of this vulnerability allows an attacker to gain unauthorized access to the console server. This can serve as a primary entry point for lateral movement into the internal management network, potentially leading to full infrastructure compromise, credential theft, and persistent backdoor installation.