CVE-2026-13580 Overview
CVE-2026-13580 is a buffer overflow vulnerability affecting the Edimax EW-7478APC wireless access point running firmware version 1.04. The flaw resides in the formQoS function within /goform/formQoS, which handles HTTP POST requests. Attackers can trigger the overflow by manipulating the selSSID argument sent to the endpoint. Remote exploitation is feasible over the network, and technical details of the exploit have been publicly disclosed. The vendor was contacted prior to disclosure but did not respond. The weakness is classified under [CWE-119] (Improper Restriction of Operations within the Bounds of a Memory Buffer).
Critical Impact
Remote attackers with low-privilege access can corrupt memory on affected Edimax EW-7478APC devices, potentially leading to arbitrary code execution or denial of service on the access point.
Affected Products
- Edimax EW-7478APC firmware version 1.04
- Component: POST Request Handler (/goform/formQoS)
- Vulnerable function: formQoS
Discovery Timeline
- 2026-06-29 - CVE CVE-2026-13580 published to NVD
- 2026-06-29 - Last updated in NVD database
Technical Details for CVE-2026-13580
Vulnerability Analysis
The vulnerability affects the QoS configuration handler in the Edimax EW-7478APC web management interface. When a POST request reaches /goform/formQoS, the formQoS function parses the selSSID parameter without enforcing adequate bounds checking. Supplying an oversized value for selSSID overwrites adjacent memory regions. This condition matches the classic pattern of [CWE-119] memory corruption in embedded HTTP daemons. The current EPSS probability is 0.445%, reflecting a limited but non-zero likelihood of near-term exploitation attempts.
Root Cause
The root cause is unsafe handling of user-controlled input in the formQoS request handler. The routine copies the selSSID argument into a fixed-size buffer without validating the length of the incoming string. Because embedded Edimax firmware typically uses strcpy-style operations on stack or heap buffers, attacker-controlled data can overwrite return addresses, function pointers, or adjacent structures.
Attack Vector
Exploitation requires network access to the device's web management interface and low-privileged authenticated access. An attacker submits a crafted POST request to /goform/formQoS containing an oversized selSSID value. Successful exploitation corrupts memory in the httpd process managing the interface. Depending on memory layout, outcomes range from process crash and denial of service to arbitrary code execution in the context of the web server. Public disclosure of the exploit increases the likelihood of opportunistic scanning against exposed devices.
See the Notion technical writeup and VulDB entry for CVE-2026-13580 for additional technical detail.
Detection Methods for CVE-2026-13580
Indicators of Compromise
- Unusually long selSSID parameter values in HTTP POST requests to /goform/formQoS
- Unexpected reboots, httpd crashes, or watchdog resets on Edimax EW-7478APC devices
- Configuration changes to QoS settings that do not correspond to legitimate administrative activity
- Outbound connections initiated by the access point to unfamiliar hosts following web interface access
Detection Strategies
- Inspect HTTP traffic to the device for POST requests targeting /goform/formQoS with parameter lengths exceeding expected SSID sizes (32 bytes per IEEE 802.11)
- Deploy network intrusion detection signatures that flag oversized selSSID values in POST bodies destined for Edimax management interfaces
- Correlate authentication events on the access point with subsequent QoS form submissions to identify anomalous administrative sessions
Monitoring Recommendations
- Log and centralize all HTTP requests to the Edimax management interface for retrospective analysis
- Alert on repeated failed HTTP requests or connection resets to the web administration port
- Monitor device uptime and process health metrics via SNMP or syslog for signs of memory corruption crashes
How to Mitigate CVE-2026-13580
Immediate Actions Required
- Restrict access to the Edimax EW-7478APC web management interface to trusted management VLANs or specific administrator hosts
- Disable remote WAN-side administration of the device if it is currently enabled
- Rotate administrative credentials for the access point to reduce exposure from any low-privileged account misuse
- Inventory environments for Edimax EW-7478APC devices running firmware 1.04 and prioritize network segmentation
Patch Information
No vendor patch has been published at the time of disclosure. According to the CVE record, the vendor was contacted before public disclosure but did not respond. Administrators should monitor the Edimax support portal and the VulDB entry for firmware updates.
Workarounds
- Place the access point behind a firewall that blocks inbound HTTP/HTTPS to the management interface from untrusted networks
- Apply access control lists to permit management traffic only from designated administrator workstations
- Consider replacing the device if it is deployed at network perimeters where exposure cannot be reduced
- Disable QoS configuration features if operationally acceptable to reduce the attack surface of the vulnerable handler
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
