CVE-2026-3798 in CF-AC100
Summary
by MITRE • 03/09/2026
A vulnerability was detected in Comfast CF-AC100 2.6.0.8. This affects the function sub_44AC14 of the file /cgi-bin/mbox-config?method=SET§ion=ping_config of the component Request Path Handler. The manipulation results in command injection. The attack may be launched remotely. The exploit is now public and may 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 • 03/14/2026
The vulnerability identified as CVE-2026-3798 represents a critical command injection flaw within the Comfast CF-AC100 wireless router firmware version 2.6.0.8. This issue resides in the Request Path Handler component, specifically within the sub_44AC14 function of the /cgi-bin/mbox-config?method=SET§ion=ping_config endpoint. The vulnerability stems from inadequate input validation and sanitization mechanisms that fail to properly handle user-supplied data passed through the ping_config section parameter. This flaw allows attackers to inject arbitrary commands that execute with the privileges of the web server process, typically running as root or with elevated system permissions. The affected device operates a web-based management interface that exposes this endpoint, making it accessible through standard HTTP requests without requiring authentication for exploitation.
The technical implementation of this vulnerability demonstrates a classic command injection attack vector where user-controllable input directly influences system command execution. When an attacker submits malicious data through the ping_config parameter, the application fails to properly escape or validate special characters that could be interpreted as shell metacharacters. This allows attackers to append additional commands to the existing ping functionality, potentially enabling complete system compromise through commands such as shell command execution, file manipulation, network scanning, or even payload delivery. The vulnerability operates at the application layer and leverages the underlying operating system's command processing capabilities, making it particularly dangerous as it can bypass traditional network security controls that monitor application traffic.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides attackers with full system control over affected devices. Remote exploitation eliminates the need for physical access or local network presence, allowing threat actors to compromise devices from anywhere on the internet. This capability enables various attack patterns including but not limited to persistent backdoor installation, network reconnaissance, lateral movement within compromised networks, and data exfiltration from connected systems. The public availability of exploit code significantly increases the risk surface as it reduces the technical barrier for exploitation. Organizations running Comfast CF-AC100 devices are particularly vulnerable since these devices are commonly deployed in residential and small office environments where security monitoring may be minimal.
Mitigation strategies for CVE-2026-3798 require immediate action from affected organizations to prevent exploitation. The primary recommendation involves firmware updates from Comfast, though the vendor's lack of response to early disclosure raises concerns about future patch availability. Network administrators should implement firewall rules blocking access to the vulnerable endpoint and consider disabling unnecessary web management interfaces. Additional protective measures include network segmentation to isolate affected devices, monitoring for unusual network traffic patterns, and implementing intrusion detection systems that can identify command injection attempts. From a security standards perspective, this vulnerability aligns with CWE-77 and CWE-88, representing command injection flaws that can lead to privilege escalation. The ATT&CK framework categorizes this under T1059.001 for command and script interpreter execution, with potential progression to T1068 for local privilege escalation and T1041 for data compression and T1071.004 for application layer protocol usage. Organizations should also consider implementing web application firewalls to filter malicious payloads and establish network monitoring procedures specifically designed to detect command injection patterns.