CVE-2025-9584: Comfast CF-N1 Firmware RCE Vulnerability

CVE-2025-9584 Overview

CVE-2025-9584 is a command injection vulnerability affecting Comfast CF-N1 firmware version 2.6.0. The flaw resides in the update_interface_png function within the /usr/bin/webmgnt binary on the device. Attackers can manipulate the interface and display_name arguments to inject arbitrary shell commands [CWE-74]. The vulnerability is exploitable over the network and requires only low-level privileges. Public disclosure of the exploit details increases the likelihood of opportunistic abuse against exposed devices.

Critical Impact

Authenticated network attackers can inject arbitrary operating system commands into the Comfast CF-N1 web management interface, leading to unauthorized command execution on the affected router.

Affected Products

• Comfast CF-N1 hardware (version 2)
• Comfast CF-N1 firmware 2.6.0
• /usr/bin/webmgnt management binary

Discovery Timeline

• 2025-08-28 - CVE-2025-9584 published to NVD
• 2026-04-29 - Last updated in NVD database

Technical Details for CVE-2025-9584

Vulnerability Analysis

The vulnerability exists in the update_interface_png function implemented in the /usr/bin/webmgnt binary on the Comfast CF-N1 router. The function processes user-supplied values from the interface and display_name parameters without proper sanitization. An attacker who can reach the web management interface can submit crafted parameter values that break out of the intended command context. The injected payload executes within the shell context invoked by the management binary. Public technical documentation describing the vulnerable code path is available in the GitHub project documentation.

Root Cause

The root cause is improper neutralization of special elements used in a command [CWE-74]. The update_interface_png handler concatenates attacker-controlled interface and display_name strings directly into a shell command invocation. The binary fails to validate, escape, or whitelist the input characters before execution.

Attack Vector

The attack is network-based and requires low-privilege authentication to the device management interface. An attacker sends a crafted HTTP request to the management endpoint backed by update_interface_png. Shell metacharacters embedded in interface or display_name are passed unsanitized to the underlying shell, achieving command injection on the embedded Linux system.

No verified proof-of-concept code is published in the NVD reference set. Additional technical context is tracked under VulDB entry #321697.

Detection Methods for CVE-2025-9584

Indicators of Compromise

• HTTP POST requests to the CF-N1 management interface containing shell metacharacters (;, &&, |, backticks) in the interface or display_name parameters.
• Unexpected child processes spawned from /usr/bin/webmgnt such as sh, wget, curl, or nc.
• Outbound connections from the router to unfamiliar hosts following management interface activity.

Detection Strategies

• Inspect web server access logs on the router for requests targeting the update_interface_png handler with non-alphanumeric characters in interface or display_name.
• Monitor management network segments for HTTP traffic to CF-N1 administrative endpoints from unauthorized client addresses.
• Capture and analyze configuration changes on the device to detect unexpected interface display name modifications.

Monitoring Recommendations

• Forward router syslog and authentication logs to a central log aggregation platform for review.
• Alert on any new outbound connections originating from the router itself, which typically should not initiate sessions to the internet.
• Track failed and successful authentications against the CF-N1 web management interface and rate-limit administrative access.

How to Mitigate CVE-2025-9584

Immediate Actions Required

• Restrict access to the CF-N1 web management interface to trusted management VLANs or jump hosts.
• Disable remote administration from the WAN interface if it is currently enabled.
• Rotate administrative credentials and enforce strong, unique passwords for all device accounts.
• Audit the device for unauthorized configuration changes, scheduled tasks, and unexpected processes.

Patch Information

No vendor advisory or patched firmware release has been listed in the public references for CVE-2025-9584. Consult the VulDB entry and the Comfast vendor support channels for updated firmware availability. Until a fix is released, treat affected devices as high-risk and apply compensating controls.

Workarounds

• Place CF-N1 devices behind a network firewall that blocks inbound access to the management port from untrusted networks.
• Restrict administrative access by source IP using upstream firewall rules where the device itself does not support ACLs.
• Replace end-of-support or unpatched CF-N1 units with currently supported hardware if no firmware fix becomes available.

# Configuration example: restrict management access at upstream firewall
# Allow only the management subnet to reach the CF-N1 admin interface
iptables -A FORWARD -s 10.10.20.0/24 -d <CF-N1-IP> -p tcp --dport 80 -j ACCEPT
iptables -A FORWARD -d <CF-N1-IP> -p tcp --dport 80 -j DROP
iptables -A FORWARD -d <CF-N1-IP> -p tcp --dport 443 -j DROP