CVE-2020-37096 Overview
CVE-2020-37096 is a cross-site request forgery [CWE-352] vulnerability in the Edimax EW-7438RPn Mini Wi-Fi range extender running firmware version 1.13. The flaw resides in the MAC filtering configuration interface, which fails to validate the origin of state-changing requests. An attacker can craft a malicious web page that, when visited by an authenticated administrator, silently submits a request to add unauthorized MAC addresses to the device's filtering rules. Successful exploitation alters network access control without user consent and requires no authentication beyond an active administrator session.
Critical Impact
Attackers can manipulate MAC filtering rules on affected Edimax range extenders, potentially permitting unauthorized devices onto the network or denying service to legitimate clients.
Affected Products
- Edimax EW-7438RPn Mini hardware
- Edimax EW-7438RPn Mini firmware version 1.13
- Wi-Fi range extender deployments using the affected firmware build
Discovery Timeline
- 2026-02-03 - CVE-2020-37096 published to NVD
- 2026-02-20 - Last updated in NVD database
Technical Details for CVE-2020-37096
Vulnerability Analysis
The Edimax EW-7438RPn web management interface accepts MAC filtering configuration changes through HTTP requests that lack anti-CSRF tokens. The device does not verify the Origin or Referer headers, nor does it require a unique per-session token tied to the form submission. Any authenticated session in the administrator's browser becomes a usable credential for an attacker-controlled page. The vulnerability targets the MAC filter configuration endpoint, which controls which clients are permitted or blocked on the wireless network. Exploitation modifies access control state on the device, mapping to CVSS impact on integrity with no confidentiality or availability impact required.
Root Cause
The root cause is missing CSRF protection on state-changing requests in the MAC filtering configuration interface. The web application does not bind form submissions to a server-issued anti-forgery token. It also does not enforce same-origin checks before accepting configuration changes.
Attack Vector
The attacker hosts a malicious page containing an auto-submitting HTML form or a scripted fetch request targeting the router's MAC filter endpoint. When an administrator authenticated to the EW-7438RPn web UI visits the page, the browser automatically attaches the session cookie. The router processes the forged request as legitimate and updates the filtering rules. User interaction is required only in the form of visiting the attacker-controlled page.
For a verified proof of concept, see Exploit-DB #48366 and the VulnCheck Advisory for Edimax CSRF.
Detection Methods for CVE-2020-37096
Indicators of Compromise
- Unexpected MAC addresses appearing in the device's MAC filter allow or deny list
- Configuration change events on the EW-7438RPn web interface that do not correlate with administrator activity
- HTTP POST requests to the MAC filtering endpoint with Referer headers pointing to external domains
Detection Strategies
- Inspect router configuration backups periodically and diff MAC filter rules against an approved baseline
- Monitor outbound HTTP traffic from administrator workstations for requests directed at the router management interface that originate from non-management browser contexts
- Review browser history and proxy logs for visits to untrusted sites coinciding with router configuration changes
Monitoring Recommendations
- Enable logging on upstream network devices to capture client MAC associations and correlate against the router's filter list
- Alert on new clients joining the wireless network shortly after administrator browsing sessions
- Track firmware version inventory across deployed Edimax devices to identify systems still running 1.13
How to Mitigate CVE-2020-37096
Immediate Actions Required
- Restrict administrative access to the EW-7438RPn web interface to a dedicated management workstation or VLAN
- Log out of the router management interface immediately after each administrative session to invalidate the session cookie
- Audit current MAC filter entries and remove any unrecognized addresses
Patch Information
No vendor patch is referenced in the published advisories at the time of NVD publication. Consult the Edimax Product Page for the latest firmware availability. Where a vendor fix is not available, organizations should evaluate replacing affected devices with hardware that receives active security maintenance.
Workarounds
- Use a separate browser profile or isolated browser exclusively for router administration to prevent cookie reuse across sites
- Change the router's default management IP and administrator credentials to reduce predictability of CSRF payloads
- Place the device behind a network segment that blocks direct browser access from general user workstations
# Example: clear browser session before and after administering the device
# (run on the administrator workstation)
# 1. Open a dedicated browser profile
# 2. Authenticate to the router web UI
# 3. Apply configuration changes
# 4. Log out and close the browser profile to discard the session cookie
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
