CVE-2026-9347 Overview
CVE-2026-9347 is an operating system (OS) command injection vulnerability affecting Edimax EW-7438RPn wireless range extenders up to firmware version 1.31. The flaw resides in the formWizSurvey function within /goform/formWizSurvey, part of the device's webs web management component. Attackers can manipulate the ip, mask, or gateway parameters to inject arbitrary operating system commands. The attack is reachable remotely over the network and the exploit has been publicly disclosed. The vendor was contacted prior to disclosure but did not respond, leaving devices unpatched.
Critical Impact
Remote attackers with low-privilege access can inject OS commands through network configuration parameters, gaining unauthorized execution on the router's underlying operating system.
Affected Products
- Edimax EW-7438RPn firmware versions up to and including 1.31
- The webs web management component
- The /goform/formWizSurvey endpoint and its formWizSurvey handler
Discovery Timeline
- 2026-05-24 - CVE-2026-9347 published to the National Vulnerability Database
- 2026-05-26 - Last updated in NVD database
Technical Details for CVE-2026-9347
Vulnerability Analysis
The vulnerability is classified under [CWE-77] Improper Neutralization of Special Elements used in a Command. The formWizSurvey handler processes network setup parameters submitted through the wizard interface. Values supplied for ip, mask, and gateway are passed to an underlying OS command without proper sanitization or neutralization of shell metacharacters. As a result, an authenticated user can append additional commands to the intended system call. Because the affected device is a consumer-grade range extender, successful exploitation can pivot attackers into the connected wireless network.
Root Cause
The root cause is the absence of input validation and command argument sanitization in the formWizSurvey function. The handler concatenates user-controlled strings directly into shell command invocations. Shell metacharacters such as ;, |, &, and backticks are not filtered, allowing arbitrary command append or substitution.
Attack Vector
The attack vector is network-based and requires low privileges, consistent with authenticated access to the web administration interface. An attacker submits a crafted HTTP request to /goform/formWizSurvey, embedding shell metacharacters within the ip, mask, or gateway POST parameters. The injected commands execute in the context of the web server process on the device. No user interaction is required after the request is sent.
No verified proof-of-concept code is included here. Technical details and the public disclosure are available in the GitHub Vulnerability Documentation and the VulDB Vulnerability #365310 entry.
Detection Methods for CVE-2026-9347
Indicators of Compromise
- HTTP POST requests to /goform/formWizSurvey containing shell metacharacters such as ;, |, &, $(), or backticks within the ip, mask, or gateway parameters.
- Unexpected outbound connections originating from the Edimax EW-7438RPn device, particularly to unknown command-and-control endpoints.
- New or unfamiliar processes running on the device after configuration wizard activity.
Detection Strategies
- Inspect web server access logs on the device, or upstream proxy logs, for requests targeting /goform/formWizSurvey with non-IP-format payloads in ip, mask, or gateway fields.
- Apply intrusion detection signatures that flag HTTP request bodies combining the formWizSurvey endpoint with shell metacharacters.
- Baseline normal administrative traffic to the device and alert on configuration requests from unexpected source addresses.
Monitoring Recommendations
- Monitor management VLANs and SOHO network segments for anomalous HTTP traffic directed at Edimax administrative interfaces.
- Track DNS queries and outbound flows from the range extender to detect post-exploitation beaconing.
- Forward router and gateway logs to a centralized log platform to correlate suspicious configuration activity with broader network events.
How to Mitigate CVE-2026-9347
Immediate Actions Required
- Restrict access to the device's web administration interface to trusted management hosts using firewall or access control lists.
- Disable remote administration on the WAN interface of the EW-7438RPn if currently enabled.
- Change default and shared administrative credentials to limit who can reach authenticated endpoints.
- Consider replacing the device, as the vendor has not responded to disclosure and no patch is available.
Patch Information
At the time of publication, Edimax has not released a security patch for CVE-2026-9347. The vendor was contacted prior to disclosure but did not respond. Monitor the VulDB Vulnerability #365310 entry for future updates on vendor remediation.
Workarounds
- Place the EW-7438RPn behind a segmented management network that is unreachable from untrusted clients and guest wireless networks.
- Block external access to TCP ports used by the device's web interface at the perimeter firewall.
- Audit and minimize the number of accounts permitted to authenticate to the web administration interface, since exploitation requires low-privilege credentials.
- If continued operation is required, schedule frequent reviews of device configuration and logs until a vendor fix is published.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
