CVE-2020-37096: Edimax EW-7438RPn CSRF Vulnerability

CVE-2020-37096 Overview

CVE-2020-37096 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the Edimax EW-7438RPn Wi-Fi range extender firmware version 1.13. The vulnerability exists in the MAC filtering configuration interface, allowing attackers to craft malicious web pages that trick authenticated users into adding unauthorized MAC addresses to the device's filtering rules without their knowledge or consent.

Critical Impact

Attackers can manipulate MAC address filtering rules on affected devices, potentially allowing unauthorized devices to connect to the network or blocking legitimate devices from accessing network resources.

Affected Products

• Edimax EW-7438RPn firmware version 1.13
• Edimax N300 Wi-Fi Range Extender series

Discovery Timeline

• 2026-02-03 - CVE-2020-37096 published to NVD
• 2026-02-04 - Last updated in NVD database

Technical Details for CVE-2020-37096

Vulnerability Analysis

This vulnerability stems from missing CSRF token validation in the MAC filtering configuration interface of the Edimax EW-7438RPn range extender. The device's web management interface fails to implement proper anti-CSRF protections, meaning it does not verify that requests to modify MAC filtering rules originate from legitimate user sessions.

When an authenticated administrator visits a malicious webpage while logged into the device's management interface, the attacker can silently submit requests to the device's MAC filtering endpoint. Because the browser automatically includes session cookies with cross-origin requests and the device lacks CSRF token verification, these malicious requests are processed as if they came from the legitimate administrator.

Root Cause

The root cause is classified under CWE-352 (Cross-Site Request Forgery). The Edimax EW-7438RPn web interface lacks anti-CSRF tokens or other request origin validation mechanisms. This allows any website to craft form submissions or JavaScript-based requests targeting the device's MAC filtering configuration endpoints, which the browser will execute with the user's existing authentication credentials.

Attack Vector

The attack requires user interaction where an authenticated administrator must visit a malicious webpage while having an active session with the device's management interface. The attacker crafts a webpage containing hidden form elements or JavaScript that automatically submits requests to the device's MAC filtering configuration endpoint. These requests can add arbitrary MAC addresses to the whitelist or blacklist, effectively allowing the attacker to grant network access to unauthorized devices or deny access to legitimate ones.

The vulnerability is exploitable over the network, requiring no authentication from the attacker's perspective since the victim's existing session is leveraged. Technical details and proof-of-concept information are available in the Exploit-DB #48366 advisory.

Detection Methods for CVE-2020-37096

Indicators of Compromise

• Unexpected MAC addresses appearing in the device's MAC filtering whitelist or blacklist
• Administrator access logs showing configuration changes that correlate with visits to external websites
• MAC filtering rules modified at times when no administrator activity was expected

Detection Strategies

• Monitor device configuration backups for unauthorized changes to MAC filtering rules
• Implement network monitoring to detect unusual traffic patterns to the device's management interface from internal hosts
• Review web proxy logs for requests to known CSRF payload hosting domains that coincide with device configuration changes

Monitoring Recommendations

• Enable logging on the Edimax device management interface if available
• Configure network monitoring solutions to alert on configuration changes to network infrastructure devices
• Implement SentinelOne Singularity to detect and prevent access to malicious web pages that may contain CSRF payloads

How to Mitigate CVE-2020-37096

Immediate Actions Required

• Log out of the device's management interface when not actively administering the device
• Access the device's management interface only from a dedicated browser profile with no other tabs open
• Restrict management interface access to specific IP addresses or VLANs if the device supports access control lists
• Consider placing the device's management interface on an isolated network segment

Patch Information

Check the Edimax Product Detail Page for firmware updates that may address this vulnerability. At the time of publication, verify with Edimax support whether a patched firmware version is available. Review the VulnCheck Advisory for additional vendor response information.

Workarounds

• Disable the web-based management interface and use alternative configuration methods if available
• Implement network-level access controls to restrict which hosts can reach the device's management interface
• Use a dedicated browser or private browsing session exclusively for device management tasks
• Consider replacing the device with a model that implements proper CSRF protections