CVE-2026-2823 Overview
A command injection vulnerability was discovered in Comfast CF-E7 firmware version 2.6.0.9. The vulnerability exists within the sub_41ACCC function in the /cgi-bin/mbox-config?method=SET§ion=ntp_timezone endpoint of the webmggnt component. An attacker can exploit this vulnerability by manipulating the timestr argument to inject and execute arbitrary system commands. The attack can be performed remotely over the network, making it a significant threat for exposed devices. The exploit for this vulnerability has been publicly disclosed.
Critical Impact
Remote attackers can execute arbitrary commands on vulnerable Comfast CF-E7 routers by exploiting command injection in the NTP timezone configuration endpoint. The vendor has not responded to responsible disclosure attempts.
Affected Products
- Comfast CF-E7 Firmware version 2.6.0.9
- Comfast CF-E7 Hardware
Discovery Timeline
- 2026-02-20 - CVE-2026-2823 published to NVD
- 2026-02-20 - Last updated in NVD database
Technical Details for CVE-2026-2823
Vulnerability Analysis
This command injection vulnerability (CWE-77) stems from insufficient input validation in the Comfast CF-E7 router's web management interface. The vulnerable function sub_41ACCC processes user-supplied input from the timestr parameter without proper sanitization before passing it to system command execution functions. This allows attackers to append malicious commands that will be executed with the privileges of the web server process.
The vulnerability is classified under CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component) and CWE-77 (Command Injection). Authentication is required to exploit this vulnerability, which provides some barrier to exploitation but does not eliminate the risk, especially in environments with weak or default credentials.
Root Cause
The root cause of this vulnerability is the failure to properly sanitize user input in the timestr argument before incorporating it into system commands. The sub_41ACCC function in the webmggnt component directly uses the user-supplied data without escaping or validating special characters that could be interpreted as command delimiters or operators by the underlying shell.
Attack Vector
The attack is network-based and targets the /cgi-bin/mbox-config?method=SET§ion=ntp_timezone endpoint on the Comfast CF-E7 router's web management interface. An authenticated attacker can craft a malicious HTTP request containing shell metacharacters (such as ;, |, &, or backticks) within the timestr parameter. When the vulnerable function processes this input, the injected commands are executed on the underlying operating system.
The attack requires network access to the router's management interface, which may be exposed on the LAN or, in some misconfigured environments, on the WAN interface. Since the exploit is publicly available, organizations using affected devices should prioritize mitigation efforts.
Detection Methods for CVE-2026-2823
Indicators of Compromise
- Unusual HTTP requests to /cgi-bin/mbox-config containing shell metacharacters in the timestr parameter
- Unexpected processes spawned by the web server process on the router
- Anomalous outbound network connections from the router to external hosts
- Modifications to router configuration files or firmware
Detection Strategies
- Monitor web server logs for requests to /cgi-bin/mbox-config?method=SET§ion=ntp_timezone with suspicious parameter values
- Implement network intrusion detection rules to identify command injection patterns in HTTP traffic to router management interfaces
- Deploy web application firewall rules to block requests containing shell metacharacters to CGI endpoints
Monitoring Recommendations
- Enable logging on network devices monitoring traffic to/from router management interfaces
- Configure alerting for any access to router management endpoints from unexpected source IP addresses
- Regularly audit router configurations for unauthorized changes
- Monitor for firmware modifications or unexpected system behavior on affected devices
How to Mitigate CVE-2026-2823
Immediate Actions Required
- Restrict access to the router's web management interface to trusted IP addresses only
- Disable remote management features if not required
- Ensure strong, unique credentials are configured for the management interface
- Consider placing affected devices behind a firewall with strict access controls
- Monitor for exploitation attempts using the detection strategies outlined above
Patch Information
No patch information is currently available from the vendor. According to the vulnerability disclosure, Comfast was contacted about this issue but did not respond. Organizations should monitor VulDB and the GitHub CVE documentation for updates regarding vendor response or patch availability.
Workarounds
- Implement network segmentation to isolate affected routers from untrusted networks
- Use access control lists (ACLs) to restrict management interface access to specific administrator IP addresses
- Consider replacing affected devices with alternative hardware from vendors with better security response practices
- Deploy a reverse proxy with input validation in front of the management interface if device replacement is not immediately feasible
# Example iptables rules to restrict management interface access
# Allow management access only from trusted administrator IP
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.100 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
