CVE-2026-77148 in CF-N1-S
Summary
by MITRE • 08/20/2026
A vulnerability was found in Comfast CF-N1-S 2.6.0.1. This impacts the function sub_44B50C of the file /cgi-bin/mbox-config?method=SET§ion=ptest_channel of the component Web Management. The manipulation results in stack-based buffer overflow. The attack can be launched remotely. The exploit has been made public and could be used.
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Analysis
by VulDB Data Team • 08/20/2026
The vulnerability identified in Comfast CF-N1-S firmware version 2.6.0.1 represents a critical security flaw within the device's web management interface, specifically targeting the mbox-config CGI script when invoked with specific parameters for channel testing. This issue is classified as CWE-121, which denotes a stack-based buffer overflow, a category of memory corruption error where a program writes data beyond the boundaries of a fixed-size buffer allocated on the call stack. The technical root cause lies in the function sub_44B50C within the /cgi-bin/mbox-config endpoint, particularly when handling input for the ptest_channel section via the SET method. In this context, the application fails to adequately validate or sanitize user-supplied data before copying it into a fixed-size buffer on the stack. This lack of bounds checking allows an attacker to supply a payload that exceeds the allocated memory space, thereby overwriting adjacent memory locations including return addresses and saved frame pointers.
The operational impact of this vulnerability is severe due to its remote exploitable nature. Since the affected component resides within the web management interface, which is typically accessible over network connections, an unauthenticated or authenticated attacker can launch a remote attack without physical access to the device. The exploitation of this stack-based buffer overflow enables arbitrary code execution on the target system with the privileges of the compromised process, often root level in embedded Linux environments. This capability allows attackers to fully compromise the integrity and availability of the network infrastructure protected by the router. Once control is established, malicious actors can install persistent backdoors, exfiltrate sensitive data such as Wi-Fi credentials or connected device information, pivot into internal networks for lateral movement, or disrupt service through denial-of-service conditions caused by memory corruption crashes.
From a threat intelligence perspective, this vulnerability aligns with MITRE ATT&CK techniques related to initial access and execution via web applications. The fact that the exploit has been made public significantly elevates the risk profile, as it lowers the barrier to entry for opportunistic attackers who may not possess advanced reverse engineering skills but can utilize existing proof-of-concept code found in public repositories or exploit markets. This widespread availability increases the likelihood of automated scanning and exploitation campaigns targeting devices running this specific firmware version across global networks. The presence of a working exploit means that defenders cannot rely solely on the obscurity of the vulnerability to maintain security posture, necessitating immediate remediation efforts rather than waiting for vendor patches in some cases where workarounds are available.
Mitigation strategies must focus primarily on updating the device firmware to a patched version released by Comfast that addresses the buffer overflow issue through proper input validation and bounds checking mechanisms. If an update is not immediately available, network-level controls should be implemented to restrict access to the web management interface, limiting it to trusted IP ranges or disabling remote administration entirely if not required for legitimate operations. Additionally, deploying intrusion detection systems with signatures capable of detecting stack-based buffer overflow attempts can provide a layer of defense against exploitation attempts while patching is underway. Security administrators should also audit other CGI endpoints within the device's web server for similar input handling flaws, as this vulnerability may indicate broader weaknesses in the application development lifecycle regarding secure coding practices and memory safety standards.