CVE-2026-13581: Edimax EW-7478APC Remote Command Injection via rootAPmac Parameter

Technical summary

CVE-2026-13581 is an OS command injection vulnerability in the Edimax EW-7478APC firmware 1.04. The POST request handler for formStaDrvSetup fails to properly sanitize the rootAPmac parameter before passing it to an OS command execution function. This results in CWE-77 (Improper Neutralization of Special Elements used in a Command) and CWE-78 (Improper Neutralization of Special Elements used in an OS Command). The vulnerability requires valid authentication credentials but no elevated privileges, and can be exploited over the network without user interaction.

Business impact

Compromise of an Edimax EW-7478APC access point could allow attackers to intercept network traffic, redirect users to malicious sites, deploy persistent backdoors, or use the device as a pivot point into your corporate or home network. The attack surface widens considerably if the access point is internet-facing or accessible to untrusted users. For organizations managing multiple Edimax devices, this could represent a significant infrastructure risk if left unpatched.

Affected systems

Edimax EW-7478APC wireless access point running firmware version 1.04 is confirmed vulnerable. Organizations should verify whether they operate this specific model and firmware version in their network inventory. The vulnerability requires network access and valid login credentials, so devices behind firewalls or with strong access controls face lower immediate risk than those publicly accessible or used in shared/guest network environments.

Exploitability

While the vulnerability requires authenticated access to exploit, this is a practical barrier rather than a strong security boundary. Many access points ship with default credentials that often go unchanged, and credentials may be guessable or obtained through social engineering. Proof-of-concept details have been publicly disclosed, making exploitation straightforward for attackers once they gain initial authentication. The CVSS 3.1 score of 6.3 (MEDIUM) reflects the authentication requirement; however, the actual risk depends heavily on credential hygiene and network segmentation in your environment.

Remediation

Immediately contact Edimax for available firmware updates or patches that address this command injection flaw. Given the vendor's reported non-responsiveness to early disclosure, patches may be delayed or unavailable. As interim mitigation, restrict network access to the device's web interface using firewall rules, network segmentation, or VPN-gated access. Change default administrative credentials to strong, unique passwords. Consider temporarily disabling remote management features if they are not essential. Monitor the device for suspicious activity and unusual command execution patterns.

Patch guidance

Check the Edimax support portal for your EW-7478APC model for firmware updates beyond 1.04. Verify patch availability against the official vendor advisory before applying. If no official patch is available, escalate to Edimax support and request a timeline. Until a fix is released, rely on network-layer controls (firewall rules, access restrictions, segmentation) to minimize exposure. Test any firmware updates in a non-production environment first.

Detection guidance

Monitor POST requests to /goform/formStaDrvSetup for unusual rootAPmac parameter values, especially those containing shell metacharacters (backticks, pipes, semicolons, ampersands, dollar signs, or parentheses). Check device logs for unexpected command execution, particularly from the web interface process. Use network intrusion detection systems to flag suspicious POST patterns. Review access logs for repeated authentication attempts or successful logins from unfamiliar IP addresses. Behavioral analysis of the access point's process execution tree may reveal injected commands distinct from normal firmware operations.

Why prioritize this

This vulnerability combines network exploitability with command injection severity, making it a meaningful security concern despite the authentication requirement. The public disclosure and lack of vendor response increase urgency. Prioritize patching or isolating Edimax EW-7478APC devices, especially those in sensitive network locations (DMZ, guest networks, customer-facing). Organizations relying heavily on Edimax infrastructure should expedite inventory checks and access control reviews.

Risk score, explained

The CVSS 3.1 score of 6.3 (MEDIUM) reflects a remotely exploitable flaw with confidentiality, integrity, and availability impact, tempered by the requirement for authenticated access. However, the actual risk in your environment may be higher if default credentials are in use, the device is internet-facing, or it sits in a trust zone with lateral movement potential. Conversely, risk may be lower if the device is firewalled, segregated, or already operating with strong access controls.

Frequently asked questions