Summary
A critical OS command injection vulnerability affects the Wavlink WL-WN530BE1-A router in the VPN upload CGI handler. Remote attackers may manipulate the Type argument to influence command execution, particularly when the endpoint is reachable without adequate authorization or input validation.
A critical OS command injection vulnerability affects the Wavlink WL-WN530BE1-A router in the VPN upload CGI handler. Remote attackers may manipulate the Type argument to influence command execution, particularly when the endpoint is reachable without adequate authorization or input validation.
Affected context
The vulnerability occurs in the /cgi-bin/uploadVpn.cgi endpoint of affected Wavlink WL-WN530BE1-A firmware. Risk increases when the endpoint is exposed to remote clients and the Type parameter is incorporated into a system command without strict validation, safe argument handling, or effective access controls.
The vulnerability occurs in the /cgi-bin/uploadVpn.cgi endpoint of affected Wavlink WL-WN530BE1-A firmware. Risk increases when the endpoint is exposed to remote clients and the Type parameter is incorporated into a system command without strict validation, safe argument handling, or effective access controls.
Exploit preconditions
- Attack surface: HTTP-accessible VPN upload CGI endpoint
- Required access: Network reachability to the affected router; authentication requirements may depend on deployment configuration
- Trigger point: Processing of the
Typeargument by the VPN upload handler - Why exploitation is possible: Attacker-controlled input may reach a
popen-based command execution path without sufficient separation between data and operating-system commands
- Attack surface: HTTP-accessible VPN upload CGI endpoint
- Required access: Network reachability to the affected router; authentication requirements may depend on deployment configuration
- Trigger point: Processing of the
Typeargument by the VPN upload handler - Why exploitation is possible: Attacker-controlled input may reach a
popen-based command execution path without sufficient separation between data and operating-system commands
Why this happens
The underlying issue is command construction that allows externally supplied data to influence an operating-system command executed through popen. Without strict allowlisting, safe process APIs, and robust argument separation, metacharacters or unexpected values may alter command behavior. This maps primarily to CWE-78: Improper Neutralization of Special Elements used in an OS Command, with CWE-77: Improper Neutralization of Special Elements in Command describing the broader command-injection class.
The underlying issue is command construction that allows externally supplied data to influence an operating-system command executed through popen. Without strict allowlisting, safe process APIs, and robust argument separation, metacharacters or unexpected values may alter command behavior. This maps primarily to CWE-78: Improper Neutralization of Special Elements used in an OS Command, with CWE-77: Improper Neutralization of Special Elements in Command describing the broader command-injection class.
Potential impact
- An attacker may execute arbitrary commands with the privileges of the router service
- The device could be reconfigured, disabled, or otherwise compromised
- Network traffic or administrative credentials may be exposed
- The router could be used for lateral movement or additional attacks
- Firmware integrity and connected-network availability could be affected
- An attacker may execute arbitrary commands with the privileges of the router service
- The device could be reconfigured, disabled, or otherwise compromised
- Network traffic or administrative credentials may be exposed
- The router could be used for lateral movement or additional attacks
- Firmware integrity and connected-network availability could be affected
General mitigation guidance
Mitigation generally focuses on preventing user-controlled data from becoming executable command syntax.
Defensive patterns include:
- Replacing shell-mediated command execution with APIs that pass fixed executable paths and structured arguments
- Enforcing a strict allowlist for accepted VPN type values
- Separating validation from command construction and rejecting unexpected input by default
- Restricting access to the VPN upload endpoint through authentication, authorization, and network segmentation
- Running service components with the minimum privileges required and limiting access to sensitive device resources
- Applying secure-by-default management-plane exposure and disabling unnecessary remote administration paths
Mitigation generally focuses on preventing user-controlled data from becoming executable command syntax.
Defensive patterns include:
- Replacing shell-mediated command execution with APIs that pass fixed executable paths and structured arguments
- Enforcing a strict allowlist for accepted VPN type values
- Separating validation from command construction and rejecting unexpected input by default
- Restricting access to the VPN upload endpoint through authentication, authorization, and network segmentation
- Running service components with the minimum privileges required and limiting access to sensitive device resources
- Applying secure-by-default management-plane exposure and disabling unnecessary remote administration paths
How teams detect issues like this
Organizations can look for this vulnerability class through:
- Static analysis rules targeting
popen, shell execution, and command construction involving request parameters - Code review checks for concatenated or interpolated user input in operating-system commands
- Tests using unexpected parameter values to confirm strict allowlisting and rejection behavior
- Web and router logs showing unusual requests to
/cgi-bin/uploadVpn.cgior abnormalTypevalues - Network monitoring for unexpected outbound connections or command-related activity from router management services
- Policy enforcement that blocks shell execution with untrusted data and requires structured process APIs
Organizations can look for this vulnerability class through:
- Static analysis rules targeting
popen, shell execution, and command construction involving request parameters - Code review checks for concatenated or interpolated user input in operating-system commands
- Tests using unexpected parameter values to confirm strict allowlisting and rejection behavior
- Web and router logs showing unusual requests to
/cgi-bin/uploadVpn.cgior abnormalTypevalues - Network monitoring for unexpected outbound connections or command-related activity from router management services
- Policy enforcement that blocks shell execution with untrusted data and requires structured process APIs
Sources
| Source | Link |
|---|---|
| gist. | gist.github.com/ |
| vuldb. | vuldb.com/ |
| vuldb. | vuldb.com/ |
| vuldb. | vuldb.com/ |
| vuldb. | vuldb.com/ |
