CVE-2026-13562 Overview
CVE-2026-13562 is a buffer overflow vulnerability in the Edimax EW-7478APC wireless access point running firmware version 1.04. The flaw resides in the formiNICSiteSurvey function handling POST requests to /goform/formiNICSiteSurvey. Attackers can trigger the overflow by manipulating the selSSID argument. The vulnerability is remotely exploitable and a public exploit has been released. The vendor was contacted before disclosure but did not respond, leaving affected devices without an official patch. The weakness is classified as [CWE-119] (improper restriction of operations within the bounds of a memory buffer).
Critical Impact
Remote attackers with low privileges can corrupt memory on the device, enabling potential code execution, device compromise, or denial of service on affected Edimax EW-7478APC access points.
Affected Products
- Edimax EW-7478APC wireless access point
- Firmware version 1.04
- formiNICSiteSurvey function in the web management interface
Discovery Timeline
- 2026-06-29 - CVE-2026-13562 published to NVD
- 2026-07-01 - Last updated in NVD database
Technical Details for CVE-2026-13562
Vulnerability Analysis
The vulnerability affects the POST request handler that services the wireless site survey feature of the Edimax EW-7478APC. When a client submits a POST request to /goform/formiNICSiteSurvey, the formiNICSiteSurvey function processes the selSSID parameter without validating its length against the destination buffer. Supplying an oversized selSSID value overwrites adjacent memory on the stack or heap.
The vulnerability is network-reachable and requires only low-level privileges. Successful exploitation impacts the confidentiality, integrity, and availability of the device. Because the affected component is the administrative web interface of an embedded device, corrupted memory can lead to arbitrary code execution in the context of the web server process, which typically runs with elevated privileges on consumer network hardware.
Root Cause
The root cause is missing bounds checking on the selSSID parameter within the formiNICSiteSurvey handler. The function copies user-controlled input into a fixed-size buffer without validating length, matching the pattern described by [CWE-119]. Embedded web handlers in Edimax devices commonly use unsafe string routines such as strcpy or sprintf on request parameters, which triggers the overflow when the input exceeds the buffer size.
Attack Vector
An authenticated attacker with access to the device's web management interface sends a crafted HTTP POST request to /goform/formiNICSiteSurvey containing an overlong selSSID field. The oversized value overflows the target buffer during processing. Attackers positioned on the same network segment, or across the internet where the management interface is exposed, can deliver the payload directly to the device.
A proof-of-concept has been publicly disclosed. Technical details are available in the Notion Site Survey Document and the VulDB CVE-2026-13562 entry.
Detection Methods for CVE-2026-13562
Indicators of Compromise
- HTTP POST requests to /goform/formiNICSiteSurvey containing unusually long selSSID parameter values
- Unexpected reboots, crashes, or web service restarts on Edimax EW-7478APC devices
- Outbound connections from the access point to unfamiliar hosts following administrative traffic
- New or modified accounts on the device management interface
Detection Strategies
- Inspect HTTP request logs on network gateways for POST requests to /goform/formiNICSiteSurvey with selSSID values exceeding typical SSID lengths (32 bytes)
- Deploy intrusion detection signatures that flag oversized parameters in POST bodies directed at Edimax /goform/ endpoints
- Monitor device syslog output for watchdog resets or memory faults correlated with administrative traffic
Monitoring Recommendations
- Track access to the device management interface and alert on connections from untrusted network segments
- Baseline normal administrative traffic patterns and flag deviations in POST payload size
- Enable remote logging from the access point to a central log store for retention and correlation
How to Mitigate CVE-2026-13562
Immediate Actions Required
- Restrict access to the device web management interface to trusted administrative networks only
- Disable remote management on the WAN interface if the feature is enabled
- Segment vulnerable access points onto isolated VLANs and block inbound HTTP/HTTPS from user networks
- Rotate administrative credentials to reduce the value of any harvested login data
Patch Information
No vendor patch is available. According to the disclosure, Edimax was contacted before publication but did not respond. Administrators should monitor the Edimax support portal for firmware updates addressing the formiNICSiteSurvey handler. Additional tracking is available at VulDB Vulnerability #374570.
Workarounds
- Place affected devices behind a firewall that blocks external access to TCP ports serving the management UI
- Replace end-of-support Edimax EW-7478APC hardware with actively maintained access points where feasible
- Require VPN authentication before any administrative session with the device
- Disable the wireless site survey feature if configuration permits
# Example: restrict management interface access with iptables on an upstream gateway
iptables -A FORWARD -p tcp -d <AP_IP> --dport 80 -s <ADMIN_SUBNET> -j ACCEPT
iptables -A FORWARD -p tcp -d <AP_IP> --dport 80 -j DROP
iptables -A FORWARD -p tcp -d <AP_IP> --dport 443 -s <ADMIN_SUBNET> -j ACCEPT
iptables -A FORWARD -p tcp -d <AP_IP> --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
