PatchSiren cyber security CVE debrief
CVE-2026-9426 Edimax CVE debrief
A stack-based buffer overflow vulnerability exists in the Edimax EW-7438RPn wireless range extender, firmware version 1.31. The vulnerability resides in the `formHwSet` function within the `/goform/formHwSet` endpoint. Multiple parameters—including `Anntena`, `Mcs`, `regDomain`, `nic0Addr`, `nic1Addr`, `wlanAddr`, `wanAddr`, `wlanSSID`, `wlanChan`, `initgain`, `txcck`, `txofdm`, and `submit-url`—are susceptible to manipulation that triggers the overflow condition. The attack vector is network-based, requires low attack complexity, and can be executed remotely by an attacker with low privileges. The CVSS 4.0 vector indicates high impacts to confidentiality, integrity, and availability. The vulnerability has been publicly disclosed with exploit availability noted, and the vendor was reportedly contacted prior to disclosure without response. The NVD entry status is currently 'Deferred'.
- Vendor
- Edimax
- Product
- EW-7438RPn
- CVSS
- HIGH 7.4
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-05-25
- Original CVE updated
- 2026-05-26
- Advisory published
- 2026-05-25
- Advisory updated
- 2026-05-26
Who should care
Organizations deploying Edimax EW-7438RPn range extenders in production environments; network administrators managing IoT device fleets; security teams monitoring for embedded device exploitation; incident responders tracking consumer-grade wireless infrastructure attacks
Technical summary
The `formHwSet` function in `/goform/formHwSet` fails to properly validate input length for multiple hardware configuration parameters. Insufficient bounds checking allows attacker-controlled data to overflow stack-allocated buffers, potentially enabling arbitrary code execution with the privileges of the web server process. The vulnerability is reachable without authentication requirements beyond low-privilege network access.
Defensive priority
HIGH
Recommended defensive actions
- Block or restrict access to the `/goform/formHwSet` endpoint on affected Edimax EW-7438RPn devices at network boundaries
- Segment IoT devices including Edimax range extenders from critical network infrastructure
- Monitor for anomalous requests to `/goform/formHwSet` containing oversized parameter values
- Apply firmware updates from Edimax if and when released; verify vendor security advisory status
- Consider replacing affected devices if vendor patch availability cannot be confirmed
- Review network logs for indicators of compromise targeting Edimax device management interfaces
Evidence notes
Vulnerability identified through Vuldb submission (ID 813894) and assigned Vuldb entry 365407. Technical details published via GitHub repository. NVD status marked as 'Deferred' as of 2026-05-26. CVSS 4.0 vector confirms network attack vector with low complexity and high impact across CIA triad. CWE-119 and CWE-121 (stack-based buffer overflow) classifications applied.
Official resources
Public disclosure occurred on 2026-05-25 with exploit availability confirmed. Vendor contact was attempted prior to disclosure without response.