PatchSiren cyber security CVE debrief
CVE-2026-9463 Edimax CVE debrief
A stack-based buffer overflow vulnerability exists in the Edimax EW-7438RPn wireless range extender firmware version 1.31. The vulnerability is located in the `formLicence` function within the `/goform/formLicence` endpoint, where improper handling of the `submit-url` argument allows remote attackers to overflow the stack buffer. The CVSS 4.0 vector indicates network attack vector with low attack complexity, low privileges required, and no user interaction needed, resulting in high impacts to confidentiality, integrity, and availability. The exploit has been publicly disclosed, and the vendor was contacted prior to disclosure but did not respond. The vulnerability status in NVD 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 wireless range extenders in production environments, particularly those with exposed management interfaces. Security teams responsible for IoT and wireless infrastructure asset protection. Network administrators managing remote or branch office connectivity solutions.
Technical summary
The vulnerability stems from insufficient bounds checking on the `submit-url` parameter in the `formLicence` function of the `/goform/formLicence` CGI endpoint. A remote attacker with low privileges can send a crafted HTTP request with an oversized `submit-url` value to trigger stack corruption. The CVSS 4.0 score of 7.4 (HIGH) reflects the network accessibility and potential for complete system compromise. The weakness classifications CWE-121 (Stack-based Buffer Overflow) and CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) apply. Public exploit availability increases immediate risk to unpatched deployments.
Defensive priority
HIGH
Recommended defensive actions
- Block or restrict access to the /goform/formLicence endpoint on affected Edimax EW-7438RPn devices at network boundaries
- Segment IoT and wireless infrastructure devices from critical network zones to limit lateral movement potential
- Monitor for anomalous HTTP requests to /goform/formLicence containing oversized or malformed submit-url parameters
- Apply firmware updates from Edimax when available; consider device replacement if vendor support is discontinued
- Review and disable remote administration interfaces on affected devices if not required for operations
Evidence notes
Vulnerability confirmed through Vuldb CNA submission and GitHub disclosure. NVD status 'Deferred' indicates pending analysis. Vendor non-response documented in CNA submission.
Official resources
2026-05-25