CVE-2026-92255 in NR255-V
Summary
by MITRE • 09/16/2026
Netcore NR255-V version 1.5.130703 contains an out-of-bounds read vulnerability in filter_arp_put_file.cgi caused by improper use of a string handling API. Attackers can trigger an unterminated buffer over-read by exploiting this flaw in the affected component, potentially exposing adjacent memory contents.
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Analysis
by VulDB Data Team • 09/16/2026
The Netcore NR255-V router running firmware version 1.5.130703 is susceptible to a critical out-of-bounds read vulnerability within its web management interface, specifically located in the filter_arp_put_file.cgi component. This flaw stems from improper implementation of string handling APIs, where the software fails to correctly validate buffer boundaries before reading data. In embedded networking devices like this router, CGI scripts often process user-supplied input directly or with insufficient sanitization. When an attacker crafts a malicious request that triggers this specific code path, the application attempts to read beyond the allocated memory buffer because it does not properly check the length of the input string against the size of the destination buffer. This results in an unterminated buffer over-read condition where the program continues reading adjacent memory locations until it encounters a null terminator or hits a protected memory boundary that causes a crash.
From a technical perspective, this vulnerability is classified under CWE-125, which denotes Out-of-bounds Read. The root cause lies in the lack of rigorous bounds checking during string operations within the CGI script. In C-based embedded systems, such errors are common when developers rely on unsafe functions like strcpy or strcat without verifying that the source data fits within the destination buffer's limits. Here, the improper use of these APIs allows an attacker to force the application to access memory regions outside its intended scope. This can lead to several adverse outcomes depending on how the operating system handles the illegal memory access. In many cases, it results in a denial of service as the process crashes due to accessing invalid or protected memory addresses. However, if the adjacent memory contains sensitive information such as authentication tokens, session cookies, cryptographic keys, or internal network configurations, the attacker could potentially exfiltrate this data through error messages or by manipulating subsequent operations that utilize the corrupted buffer state.
The operational impact of this vulnerability is significant for both individual users and enterprise networks relying on Netcore hardware. A successful exploitation can lead to a complete denial of service, rendering the router inaccessible and disrupting network connectivity for all devices connected to it. This requires physical access or administrative credentials to reboot the device if remote patching is not available via an automated update mechanism. Furthermore, in scenarios where the memory leak provides actionable intelligence, attackers could use the exposed data to facilitate further attacks such as session hijacking or privilege escalation within the local network segment. The vulnerability also aligns with MITRE ATT&CK technique T1083, which covers File and Directory Discovery, although in this context it is more accurately described as an information disclosure vector that aids reconnaissance. It reflects a broader category of weaknesses often seen in IoT devices where security testing during development phases may be insufficient compared to resource constraints or time-to-market pressures.
Mitigation strategies for this vulnerability primarily involve applying the latest firmware updates provided by Netcore, which should include patches addressing the string handling logic in filter_arp_put_file.cgi. Until such a patch is available and deployed, network administrators can implement compensating controls at the perimeter firewall level to restrict access to the router's management interface from untrusted networks. This includes limiting HTTP/HTTPS traffic destined for port 80 or 443 on the device's LAN IP address to only trusted internal subnets. Additionally, disabling unnecessary CGI services if they are not required can reduce the attack surface. It is crucial for organizations to maintain an accurate inventory of their IoT assets and ensure that firmware versions are monitored regularly against vendor security advisories. Regular vulnerability scanning focused specifically on embedded web interfaces can help identify similar misconfigurations or outdated software components before they are exploited by malicious actors seeking to compromise network integrity.