PatchSiren cyber security CVE debrief
CVE-2026-9425 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 `formWlanMP` function within the `/goform/formWlanMP` endpoint. Multiple parameters—including `ateFunc`, `ateGain`, `ateTxCount`, `ateChan`, `ateRate`, `ateMacID`, various `e2pTxPower` and `e2pTx2Power` parameters, `ateTxFreqOffset`, `ateMode`, `ateBW`, `ateAntenna`, `e2pTxFreqOffset`, `e2pTxPwDeltaB`, `e2pTxPwDeltaG`, `e2pTxPwDeltaMix`, `e2pTxPwDeltaN`, and `readE2P`—are susceptible to manipulation that triggers the overflow condition. The vulnerability is remotely exploitable and carries a CVSS 4.0 score of 7.4 (HIGH severity). Public exploit disclosure has occurred, increasing immediate risk. The vendor was reportedly contacted prior to disclosure but did not respond. The vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-121 (Stack-based Buffer Overflow).
- 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 remote or branch office wireless infrastructure; security teams responsible for embedded device and IoT security posture; incident responders tracking exploitation of publicly disclosed router vulnerabilities
Technical summary
The Edimax EW-7438RPn firmware 1.31 contains a stack-based buffer overflow in its wireless configuration form handler. The `formWlanMP` function fails to properly validate input length across numerous ATE (Advanced Test Equipment) and EEPROM-related parameters before copying data to stack-allocated buffers. This allows authenticated remote attackers to overwrite return addresses and achieve arbitrary code execution. The attack surface is exposed through the device's web management interface on the `/goform/formWlanMP` endpoint. The CVSS 4.0 scoring reflects high impacts across confidentiality, integrity, and availability with a proof-of-concept exploit publicly available, though the attack requires low-privileged authentication.
Defensive priority
critical
Recommended defensive actions
- Immediately isolate affected Edimax EW-7438RPn devices from untrusted networks or internet exposure
- Apply network segmentation to restrict access to device management interfaces
- Monitor for suspicious requests to /goform/formWlanMP endpoint containing oversized parameter values
- Consider disabling remote management features if not essential for operations
- Contact Edimax directly for firmware update status and estimated patch availability
- Implement intrusion detection signatures for buffer overflow patterns targeting embedded device form handlers
- Prepare incident response procedures for potential device compromise given public exploit availability
Evidence notes
Vulnerability confirmed through VulDB CNA submission and public GitHub disclosure. CVSS 4.0 vector indicates network attack vector with low attack complexity, low privileges required, and no user interaction needed. Impact confidentiality, integrity, and availability ratings are all HIGH. Exploit maturity marked as 'P' (Proof-of-concept).
Official resources
Public exploit disclosure confirmed; vendor non-responsive to prior contact