CVE-2026-120241 in RG-ES205GC
Summary
by MITRE • 11/01/2026
A vulnerability was identified in Ruijie RG-ES205GC, RG-ES206GC-P, RG-ES208GC, RG-ES210GC-LP and RG-ES210GS-P ESW_1.0(1)B1P48. Impacted is an unknown function of the file httpupg.cgi of the component Local Firmware Upgrade Interface. The manipulation leads to buffer overflow. It is possible to initiate the attack remotely. The exploit is publicly available and might be used. The vendor was contacted early about this disclosure but did not respond in any way.
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Analysis
by VulDB Data Team • 11/01/2026
The identified vulnerability affects a range of Ruijie Networks managed switches, specifically models RG-ES205GC, RG-ES206GC-P, RG-ES208GC, RG-ES210GC-LP, and RG-ES210GS-P running firmware version ESW_1.0(1)B1P48 or potentially earlier versions within the same codebase. The flaw resides in the Local Firmware Upgrade Interface, specifically within an unknown function of the httpupg.cgi script component. This CGI (Common Gateway Interface) application is responsible for handling file uploads and processing firmware updates via HTTP requests. In this specific instance, the vulnerability manifests as a buffer overflow condition triggered by improper bounds checking when processing input data sent to the affected function. Buffer overflows occur when a program writes more data to a fixed-length block of memory than it can hold, causing adjacent memory locations to be overwritten with potentially malicious code or arbitrary values. This type of flaw is classified under CWE-120: Buffer Copy without Checking Size of Input and represents one of the most critical categories of software vulnerabilities due to its potential for remote code execution.
The operational impact of this vulnerability is severe because it allows an attacker to initiate a remote attack against the targeted network infrastructure. Since the httpupg.cgi interface typically listens on standard web ports, such as port 80 or 443, an adversary with network connectivity to the management interface can craft and send specially crafted HTTP requests containing oversized payloads. By exploiting the buffer overflow in the firmware upgrade process, a skilled attacker could achieve arbitrary code execution on the device's operating system. This would likely result in full compromise of the switch, allowing the attacker to pivot into other parts of the internal network, intercept sensitive traffic, or use the compromised device as part of a botnet. The severity is further amplified by the fact that the exploit for this vulnerability is publicly available. Publicly accessible exploits significantly lower the barrier to entry for attackers, increasing the likelihood of automated scanning and exploitation attempts across the internet. Organizations relying on these switches are at immediate risk if they have not implemented appropriate network segmentation or access controls.
From a threat intelligence perspective, this vulnerability aligns with ATT&CK techniques related to Initial Access via Web Services (T1190) and potentially Command and Scripting Interpreter execution depending on how the overflow is leveraged for code injection. The lack of response from Ruijie Networks regarding early disclosure raises concerns about the vendor's security patch management lifecycle. Without an official firmware update or patch, administrators must rely entirely on compensating controls to mitigate this risk. It is critical that network architects review their current configurations and implement strict access control lists (ACLs) to restrict HTTP/HTTPS traffic destined for the switch management interfaces only from trusted administrative subnets. Additionally, disabling unused services such as Telnet and FTP, if present, reduces the attack surface further.
To mitigate this vulnerability in the absence of a vendor patch, organizations should enforce network-level isolation for all managed switches. Placing these devices behind firewalls that explicitly deny inbound HTTP traffic from untrusted networks is essential. If remote management via web interface is not strictly required, it should be disabled entirely in favor of secure alternatives like SSH or SNMPv3 with strong authentication. Regular vulnerability scanning and continuous monitoring for anomalous network behavior can help detect exploitation attempts early. Given the public availability of the exploit, proactive defense mechanisms such as Intrusion Prevention Systems (IPS) signatures targeting this specific buffer overflow pattern are highly recommended to block malicious payloads before they reach the vulnerable application layer. Until a patched firmware version is released by Ruijie Networks, maintaining strict network segmentation and limiting exposure of management interfaces remains the most effective strategy for preserving the integrity and availability of these critical networking components.