CVE-2026-9297 Overview
CVE-2026-9297 is a command injection vulnerability [CWE-74] affecting the Edimax BR-6428NS wireless router running firmware version 1.10. The flaw resides in the formWlbasic function within /goform/formWlbasic, which is part of the device's POST request handler. Attackers can manipulate the repeaterSSID parameter to inject operating system commands processed by the router. The attack is initiated over the network and the exploit has been disclosed publicly. The vendor was contacted before disclosure but did not respond, leaving affected devices without an official patch.
Critical Impact
Authenticated network attackers can inject arbitrary commands through the repeaterSSID parameter, potentially gaining control over the router's underlying operating system.
Affected Products
- Edimax BR-6428NS wireless router
- Firmware version 1.10
- The formWlbasic POST request handler component
Discovery Timeline
- 2026-05-23 - CVE-2026-9297 published to NVD
- 2026-05-26 - Last updated in NVD database
Technical Details for CVE-2026-9297
Vulnerability Analysis
The vulnerability is a command injection flaw classified under [CWE-74], improper neutralization of special elements in output used by a downstream component. The Edimax BR-6428NS exposes a web-based administration interface that processes POST requests through CGI-style form handlers. One of these handlers, formWlbasic, manages wireless basic configuration including repeater settings.
The repeaterSSID argument passed to formWlbasic is not properly sanitized before being incorporated into a system-level command. Attackers can append shell metacharacters to the SSID value, causing the router to execute attacker-controlled commands with the privileges of the web server process, typically root on embedded SOHO devices.
The EPSS score is 1.058% with a percentile of 77.904, indicating elevated exploitation probability relative to most CVEs. A public exploit disclosure exists, and the vendor has not issued a fix.
Root Cause
The root cause is missing input validation and improper neutralization of shell metacharacters in the repeaterSSID POST parameter. The firmware passes user-supplied SSID data directly into a command string evaluated by a shell interpreter without sanitization or use of safe APIs such as execve with argument arrays.
Attack Vector
An attacker with network access to the router's web interface sends a crafted POST request to /goform/formWlbasic containing a malicious repeaterSSID value. The CVSS 4.0 vector indicates the attack requires low privileges and no user interaction. Because the public disclosure includes exploitation details, weaponization barriers are minimal.
No verified exploit code is republished here. See the Notion technical writeup and the VulDB entry #365244 for the disclosed proof-of-concept.
Detection Methods for CVE-2026-9297
Indicators of Compromise
- POST requests to /goform/formWlbasic containing shell metacharacters such as ;, |, `, $(), or && in the repeaterSSID parameter.
- Unexpected outbound connections originating from the router to attacker-controlled infrastructure.
- Configuration changes to wireless repeater settings that were not initiated by an administrator.
Detection Strategies
- Inspect HTTP request bodies destined for the router admin interface for non-printable or shell-special characters in SSID fields.
- Monitor router syslog output for unexpected process executions or modified startup scripts.
- Baseline router firmware integrity and alert on unauthorized binary or configuration file changes.
Monitoring Recommendations
- Restrict management interface access to a dedicated VLAN and log all administrative authentication events.
- Forward router and gateway logs to a centralized log platform for correlation with broader network telemetry.
- Alert on lateral movement attempts originating from network infrastructure devices.
How to Mitigate CVE-2026-9297
Immediate Actions Required
- Disable remote administration on the Edimax BR-6428NS and limit web management access to trusted internal hosts only.
- Change default and weak administrative credentials, since the attack vector requires low-privilege authentication.
- Place the affected router behind a network segment that restricts inbound traffic to the management interface.
- Evaluate replacement of the BR-6428NS with a supported device, since the vendor has not responded to disclosure.
Patch Information
No vendor patch is available. According to the CVE record, Edimax was contacted prior to disclosure but did not respond. Organizations operating the BR-6428NS 1.10 should treat the device as unsupported for security purposes and plan migration to a maintained platform.
Workarounds
- Block external access to TCP ports used by the router's web administration interface at the perimeter firewall.
- Disable the wireless repeater feature if it is not required, reducing the attack surface around formWlbasic.
- Apply Access Control Lists restricting which internal hosts can reach the router's management plane.
- Monitor for and decommission end-of-life Edimax BR-6428NS units across the environment.
# Example: restrict router admin interface to a single management host
# Replace 192.0.2.10 with your authorized management workstation
# and 198.51.100.1 with the router's LAN IP
iptables -A FORWARD -s 192.0.2.10 -d 198.51.100.1 -p tcp --dport 80 -j ACCEPT
iptables -A FORWARD -d 198.51.100.1 -p tcp --dport 80 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
