CVE-2026-13583: Edimax EW-7478APC Buffer Overflow – Authentication Required RCE

Technical summary

CVE-2026-13583 is a stack-based buffer overflow (CWE-119, CWE-120) in the Edimax EW-7478APC firmware version 1.04. The vulnerability exists in the formUSBFolder function of the /goform/formUSBFolder endpoint, which handles POST requests. Insufficient input validation on the ShareName and SelectName parameters allows an authenticated attacker to write beyond allocated buffer boundaries. The attack vector is network-accessible, requires low complexity exploitation, and demands user authentication (PR:L). The impact scope is unchanged, with confidentiality, integrity, and availability all fully compromised (C:H/I:H/A:H). CVSS v3.1 score is 8.8 (HIGH).

Business impact

Organizations deploying Edimax EW-7478APC access points for USB storage sharing face potential device compromise and denial of service. An authenticated attacker (such as a rogue employee or attacker with valid credentials) can destabilize or fully compromise the access point, potentially leading to data exfiltration from shared USB devices, network segmentation bypass, or extended downtime. Given public disclosure and lack of vendor response, the window for undetected exploitation is open indefinitely unless network-level mitigations are implemented.

Affected systems

Edimax EW-7478APC version 1.04 is confirmed vulnerable. Organizations should verify whether they deploy this exact model and firmware version. Check device management systems or physical inventory labels for version confirmation. Edimax has not released updated firmware information in response to early disclosure, so users should assume no patch is currently available from the vendor.

Exploitability

Exploitability is moderate-to-high. The vulnerability requires network access and prior authentication to the device—typical for local network or remote access scenarios where admin credentials have been obtained or user roles exist with USB folder management permissions. Proof-of-concept code is already public, lowering the technical barrier for exploitation. However, the attacker must successfully craft input that exceeds buffer boundaries without causing immediate detection, which remains non-trivial depending on the exact buffer layout and security features present.

Remediation

Check with Edimax for firmware updates for the EW-7478APC. If no patch is available, consider the following interim controls: disable USB folder sharing if not operationally necessary; restrict network access to the device's management interface (port 80/443) to trusted administrative hosts only; implement strong authentication policies and audit access logs for suspicious activity; and evaluate replacement with a wireless access point from a vendor with active security support. If USB sharing must remain active, isolate the device on a separate administrative VLAN.

Patch guidance

Verify the latest firmware version available from Edimax support or the vendor advisory for model EW-7478APC. At time of publication (June 2026), the vendor had not responded to early disclosure and no official patch version is documented. Contact Edimax technical support directly or monitor their security advisories for firmware release notifications. Apply patches to a test unit before production deployment to ensure no regression in USB sharing functionality.

Detection guidance

Monitor for POST requests to /goform/formUSBFolder with unusually long or malformed ShareName and SelectName parameter values. Inspect HTTP request logs for parameter injection attempts or control characters. Watch device system logs (if accessible) for crashes or unexpected reboots of the EW-7478APC. Use network-based intrusion detection to flag requests to this endpoint from non-administrative subnets. If the device supports syslog export, enable it and forward logs to a central security information event management (SIEM) system for correlation and alerting.

Why prioritize this

Despite a CVSS score of 8.8, this vulnerability warrants immediate attention due to three compounding factors: (1) proof-of-concept code is publicly available, dramatically shortening the time-to-exploit; (2) the vendor has not responded or provided a patch, leaving no clear remediation path; (3) the affected device is a network perimeter component (wireless access point) with access to USB storage and local network resources. Organizations should assume active exploitation is possible.

Risk score, explained

The CVSS v3.1 score of 8.8 reflects a network-accessible, low-complexity attack that requires authentication but yields complete compromise of confidentiality, integrity, and availability. The HIGH severity rating is justified by full system impact. Contextually, the score is compounded by public exploit availability and lack of vendor response, effectively increasing operational risk beyond the base CVSS assessment.

Frequently asked questions