CVE-2026-34794: Endian Firewall RCE Vulnerability

CVE-2026-34794 Overview

CVE-2026-34794 is a command injection vulnerability (CWE-78) affecting Endian Firewall version 3.3.25 and prior versions. The vulnerability allows authenticated users to execute arbitrary operating system commands via the DATE parameter to /cgi-bin/logs_ids.cgi. The DATE parameter value is used to construct a file path that is passed to a Perl open() call, which allows command injection due to an incomplete regular expression validation.

Critical Impact

Authenticated attackers can achieve full system compromise by injecting arbitrary OS commands through the DATE parameter, potentially leading to complete control of the firewall appliance and network infrastructure.

Affected Products

• Endian Firewall version 3.3.25
• Endian Firewall versions prior to 3.3.25
• Endian Firewall Community editions running vulnerable CGI scripts

Discovery Timeline

• 2026-04-02 - CVE CVE-2026-34794 published to NVD
• 2026-04-02 - Last updated in NVD database

Technical Details for CVE-2026-34794

Vulnerability Analysis

This command injection vulnerability exists within the IDS logs CGI script (/cgi-bin/logs_ids.cgi) of Endian Firewall. The core issue stems from improper input validation of the DATE parameter, which is subsequently used to construct a file path for a Perl open() function call.

Perl's open() function has historically been a source of command injection vulnerabilities when used with untrusted input. When the two-argument form of open() is used, special characters in the filename can be interpreted as shell metacharacters, enabling command execution. The DATE parameter undergoes validation through a regular expression, but the regex is incomplete and fails to properly sanitize all dangerous characters or command injection sequences.

The vulnerability requires authentication to exploit, which provides some level of access control. However, any user with valid credentials to the Endian Firewall web interface can leverage this flaw to execute commands with the privileges of the web server process. Given that firewall appliances typically run with elevated privileges to manage network configurations, successful exploitation can result in complete compromise of the security perimeter.

Root Cause

The root cause is an incomplete regular expression validation applied to the DATE parameter before it is used in a Perl open() call. The validation logic fails to account for all shell metacharacters and command injection techniques, allowing attackers to bypass the input filtering and inject arbitrary commands into the file path argument.

Attack Vector

The attack is conducted over the network against the web management interface of the Endian Firewall. An authenticated attacker crafts a malicious HTTP request to /cgi-bin/logs_ids.cgi with a specially formatted DATE parameter containing command injection payloads.

The injected commands bypass the incomplete regex validation and are executed when the Perl open() function processes the constructed file path. Common injection techniques may include pipe characters, backticks, or other shell metacharacters that trigger command execution within the Perl environment.

For detailed technical information about this vulnerability, refer to the VulnCheck Advisory on Endian Firewall.

Detection Methods for CVE-2026-34794

Indicators of Compromise

• Unusual HTTP requests to /cgi-bin/logs_ids.cgi containing shell metacharacters in the DATE parameter
• Unexpected processes spawned by the web server process on the Endian Firewall appliance
• Evidence of command execution artifacts in web server access logs with encoded or suspicious DATE values
• Unauthorized outbound connections from the firewall appliance to external hosts

Detection Strategies

• Monitor web server access logs for requests to /cgi-bin/logs_ids.cgi with anomalous DATE parameter values
• Implement web application firewall (WAF) rules to detect and block command injection patterns in CGI parameters
• Deploy endpoint detection on the firewall appliance to identify unauthorized process execution
• Analyze network traffic for suspicious POST requests targeting the vulnerable endpoint

Monitoring Recommendations

• Enable detailed logging for all CGI script access on Endian Firewall devices
• Configure SIEM alerts for patterns indicative of command injection attempts in web logs
• Monitor for unexpected system changes or new user accounts created on the firewall appliance
• Implement file integrity monitoring on critical Endian Firewall system directories

How to Mitigate CVE-2026-34794

Immediate Actions Required

• Restrict access to the Endian Firewall web management interface to trusted networks only
• Implement IP-based access controls to limit which hosts can reach /cgi-bin/logs_ids.cgi
• Review and audit all user accounts with access to the Endian Firewall web interface
• Consider disabling the IDS logs functionality if not required until a patch is available

Patch Information

No official patch information is currently available. Organizations should monitor the Endian Help Community Section for security updates and patch releases addressing this vulnerability.

Workarounds

• Place the Endian Firewall management interface behind an additional authentication layer or VPN
• Use firewall rules to restrict management interface access to specific administrator IP addresses
• Implement a reverse proxy with strict input validation in front of the CGI scripts
• Consider temporarily blocking access to /cgi-bin/logs_ids.cgi if the IDS logging feature is not essential

# Example: Restrict management interface access via iptables (adjust IPs as needed)
# Block all access to management port except from trusted admin network
iptables -A INPUT -p tcp --dport 10443 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 10443 -j DROP