CVE-2026-75363 Overview
CVE-2026-75363 is a remote code execution vulnerability in the Comfast CF-WR630AX wireless router running firmware version 2.7.0.2. The flaw resides in the /usr/bin/webmgnt binary and the /cgi-bin/mbox-config endpoint. Attackers can abuse the timestr and display_n parameters to execute arbitrary code on the device. A public proof-of-concept has been published in a GitHub IoT vulnerability repository.
Critical Impact
Remote attackers can execute arbitrary code on affected Comfast CF-WR630AX routers by supplying crafted values to the timestr and display_n parameters processed by /cgi-bin/mbox-config.
Affected Products
- Comfast CF-WR630AX wireless router
- Firmware version 2.7.0.2
- Web management binary /usr/bin/webmgnt and CGI handler /cgi-bin/mbox-config
Discovery Timeline
- 2026-08-26 - CVE-2026-75363 published to NVD
- 2026-08-26 - Last updated in NVD database
Technical Details for CVE-2026-75363
Vulnerability Analysis
The Comfast CF-WR630AX exposes a web management interface implemented in the /usr/bin/webmgnt binary. The binary handles requests to /cgi-bin/mbox-config, which parses parameters supplied over HTTP. The timestr and display_n parameters are consumed without proper input validation before being incorporated into system-level operations.
Because the parameter values reach a sensitive execution context inside the router firmware, a remote attacker who can send HTTP requests to the device can trigger arbitrary code execution. The vulnerability sits in embedded router firmware, so successful exploitation runs code within the router's operating environment rather than a user-space application.
Root Cause
The root cause is insufficient sanitization of attacker-controlled HTTP parameters in the mbox-config CGI handler. Values passed through timestr and display_n are trusted by webmgnt and used in a way that permits code execution. This is a common pattern in consumer IoT firmware where CGI parameters flow into shell invocations or unbounded memory operations without validation.
Attack Vector
Exploitation requires network access to the router's management interface. An attacker sends a crafted HTTP request to /cgi-bin/mbox-config with malicious values in the timestr or display_n parameters. If the management interface is reachable from the WAN or the attacker is on the local network, exploitation succeeds without authentication controls stopping the request.
For technical details, see the GitHub PoC Repository. No verified exploit code is reproduced here.
Detection Methods for CVE-2026-75363
Indicators of Compromise
- HTTP requests to /cgi-bin/mbox-config containing unusual shell metacharacters, backticks, or long payloads in the timestr or display_n parameters.
- Unexpected outbound connections originating from the router to attacker-controlled infrastructure after web management access.
- New processes, cron entries, or modified startup scripts on the router that were not created by the administrator.
Detection Strategies
- Inspect network traffic to the router's management interface for POST or GET requests targeting /cgi-bin/mbox-config with abnormal parameter content.
- Baseline normal administrative access patterns and alert on management-plane requests from unfamiliar source addresses.
- Correlate router web management access with subsequent anomalous DNS lookups or outbound traffic from the device.
Monitoring Recommendations
- Forward router syslog and HTTP access logs, where available, into a centralized log platform for retention and query.
- Monitor for changes to router firmware versions, running processes, and configuration files across managed devices.
- Alert on any exposure of the router web management interface to the WAN or untrusted network segments.
How to Mitigate CVE-2026-75363
Immediate Actions Required
- Restrict access to the router's web management interface to trusted management networks and disable WAN-side administration.
- Change default administrative credentials and enforce strong passwords on all router accounts.
- Audit connected Comfast CF-WR630AX devices running firmware 2.7.0.2 and treat them as exposed until remediated.
Patch Information
No vendor patch or advisory is referenced in the NVD entry at publication. Consult Comfast for updated firmware and monitor the GitHub PoC Repository and the vendor's support channels for remediation updates.
Workarounds
- Place affected routers behind a segmented management VLAN with strict ACLs limiting who can reach /cgi-bin/mbox-config.
- Disable remote administration features that expose the web management interface to the internet.
- Replace the device with a supported model if no firmware update is released for CF-WR630AX version 2.7.0.2.
# Example: block external access to the router web UI on an upstream firewall
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -i <wan_iface> -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -i <wan_iface> -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
