CVE-2025-55591: Totolink A3002r Firmware RCE Vulnerability

CVE-2025-55591 Overview

CVE-2025-55591 is a critical command injection vulnerability affecting the TOTOLINK A3002R router firmware version 4.0.0-B20230531.1404. The vulnerability exists in the devicemac parameter within the formMapDel endpoint, allowing attackers to execute arbitrary operating system commands on the affected device. This type of vulnerability (CWE-77: Command Injection) is particularly dangerous in network infrastructure devices, as it can provide attackers with complete control over the router and the ability to pivot to other devices on the network.

Critical Impact

Unauthenticated remote attackers can execute arbitrary commands on the router with full system privileges, potentially leading to complete device compromise, network interception, and lateral movement to connected devices.

Affected Products

• TOTOLINK A3002R Firmware version 4.0.0-B20230531.1404
• TOTOLINK A3002R Hardware

Discovery Timeline

• 2025-08-18 - CVE-2025-55591 published to NVD
• 2025-08-21 - Last updated in NVD database

Technical Details for CVE-2025-55591

Vulnerability Analysis

This command injection vulnerability stems from insufficient input validation in the router's web management interface. The formMapDel endpoint processes the devicemac parameter without properly sanitizing user-supplied input before passing it to system shell commands. Since the attack can be executed over the network without authentication and requires no user interaction, it poses a significant risk to any exposed TOTOLINK A3002R router running the vulnerable firmware.

The vulnerability allows attackers to inject arbitrary shell commands that execute with root privileges on the underlying Linux-based operating system. Successful exploitation grants complete control over the router, including the ability to modify network configurations, intercept traffic, install persistent backdoors, and use the compromised device as a pivot point for further attacks.

Root Cause

The root cause of this vulnerability is improper input validation (CWE-77: Improper Neutralization of Special Elements used in a Command). The formMapDel endpoint fails to sanitize the devicemac parameter, allowing shell metacharacters and command separators to be interpreted by the underlying system shell. When user-controlled input is passed directly to system commands without proper escaping or validation, attackers can break out of the intended command context and execute arbitrary code.

Attack Vector

The attack vector for CVE-2025-55591 is network-based, requiring no authentication or user interaction. An attacker with network access to the router's web management interface can craft a malicious HTTP request to the formMapDel endpoint with a specially crafted devicemac parameter value. By including shell metacharacters such as semicolons, backticks, or pipe characters, the attacker can inject additional commands that execute on the target system.

The vulnerability is documented in a public proof-of-concept repository demonstrating the exploitation technique. The injection point in the devicemac parameter allows attackers to append arbitrary commands that the router's Boa web server passes to the system shell for execution.

Detection Methods for CVE-2025-55591

Indicators of Compromise

• Unexpected HTTP requests to the /boafrm/formMapDel endpoint from external or unauthorized IP addresses
• Anomalous process execution spawned by the web server process (Boa)
• Unusual outbound network connections from the router to unknown external hosts
• Modified router configuration files or unexpected user accounts

Detection Strategies

• Monitor web server logs for requests to the formMapDel endpoint containing shell metacharacters (;, |, `, $()) in the devicemac parameter
• Implement network intrusion detection rules to identify command injection patterns in HTTP traffic destined for TOTOLINK router management interfaces
• Deploy anomaly detection for process creation events on network devices where possible

Monitoring Recommendations

• Enable and centralize logging for router management interface access
• Monitor for unexpected changes to router configurations or firmware
• Implement network segmentation to isolate router management interfaces from untrusted networks
• Use threat intelligence feeds to identify connections to known malicious infrastructure originating from network devices

How to Mitigate CVE-2025-55591

Immediate Actions Required

• Restrict access to the router's web management interface to trusted networks or specific IP addresses only
• Disable remote management access from the WAN interface if not required
• Implement firewall rules to block external access to the router's management ports
• Monitor for any signs of compromise and consider reimaging devices if suspicious activity is detected

Patch Information

At the time of publication, no official patch has been released by TOTOLINK for this vulnerability. Check the TOTOLINK support website for firmware updates addressing CVE-2025-55591. Organizations should prioritize patching once an update becomes available, given the critical severity and network-accessible attack vector.

Workarounds

• Disable the web management interface entirely if not operationally required
• Place the router's management interface behind a VPN or jump host to limit exposure
• Implement strong access control lists (ACLs) to restrict management access to specific administrator IP addresses
• Consider replacing vulnerable devices with alternative hardware if patches are not forthcoming

# Example firewall rules to restrict management access (adapt to your environment)
# Block external access to web management port (typically 80 or 8080)
iptables -A INPUT -i eth0 -p tcp --dport 80 -j DROP
iptables -A INPUT -i eth0 -p tcp --dport 8080 -j DROP

# Allow management access only from trusted admin network
iptables -A INPUT -s 192.168.1.0/24 -p tcp --dport 80 -j ACCEPT