Critical Remote Overflow in Wavlink Router Firmware Exposes Device to Exploitation
The National Vulnerability Database lists a CVSS 10 critical flaw in Wavlink WL-WN530BE1-A firmware version 251117, allowing remote attackers to exploit a buffer overflow via HTTP headers.
Key points
- The National Vulnerability Database assigns CVE-2026-109109 a CVSS 10 critical severity rating for the Wavlink router vulnerability.
- Attackers can trigger a stack-based buffer overflow by manipulating the HTTP_COOKIE or X-Cmd arguments in the Settings Export CGI component.
- Public exploit code is now available, and the vendor was contacted early regarding this disclosure.
The National Vulnerability Database published a record for CVE-2026-109109, identifying a critical remote vulnerability in Wavlink router firmware. This flaw affects the WL-WN530BE1-A model running version 251117 and allows attackers to initiate an attack remotely by manipulating specific HTTP request headers. The vulnerability is rated as critical with a CVSS score of 10.
At a glance
- CVE
- CVE-2026-109109
- Product
- Wavlink WL-WN530BE1-A
- CVSS
- 10 Critical
- Weakness
- stack-based buffer overflow
- Exploited
- No known exploitation
The issue resides in the `strcpy` function within the `/cgi-bin/ExportAllSettings.cgi` file. This component is part of the Settings Export CGI service on the device. When an attacker sends a crafted request with manipulated `HTTP_COOKIE` or `X-Cmd` arguments, it results in a stack-based buffer overflow. This type of weakness is classified under CWE-121 and CWE-119 in the Common Weakness Enumeration.
Technical Context and Disclosure
The vulnerability allows for remote initiation, meaning an attacker can initiate the attack remotely without physical access. The National Vulnerability Database notes that the exploit is now public and may be used. This public availability indicates that the method to exploit the flaw is accessible to potential attackers.
The disclosure process involved early contact with the vendor. According to the NVD record, Wavlink was contacted early about this disclosure. The record does not mention the current status of any remediation efforts or patches from the vendor.
Affected Systems and Scope
Only one specific product configuration is listed as affected in the official record. The Wavlink WL-WN530BE1-A router running firmware version 251117 is the sole target identified for CVE-2026-109109. Users of other Wavlink models or different firmware versions are not mentioned in this specific vulnerability record.
The impact of this vulnerability is severe due to its remote nature. A stack-based buffer overflow in a CGI script is a significant security concern. That suggests network administrators should treat this as an urgent priority if they manage this specific hardware.
What should you do?
Network operators should verify if they are running the affected firmware version on Wavlink WL-WN530BE1-A devices. Since no fix has been confirmed yet, immediate mitigation may involve isolating the device from untrusted networks. Monitoring for unusual traffic patterns related to the ExportAllSettings.cgi endpoint is also advisable.
What to do and how to stay safe: Wavlink
- Check your Wavlink WL-WN530BE1-A router firmware version to see if it matches the affected 251117 build listed in the NVD record.
- Restrict external access to the router's administration interface, particularly blocking access to CGI scripts like ExportAllSettings.cgi from untrusted networks.
- Monitor network logs for unusual HTTP requests containing manipulated HTTP_COOKIE or X-Cmd headers targeting the device's IP address.
- Once the vendor provides an update, apply the security patch immediately to resolve the stack-based buffer overflow vulnerability.
Step-by-step guide: Risk Based Vulnerability Management: Prioritize Fixes by Actual Threat
General security guidance from the Threat Times newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
What is the CVSS score for CVE-2026-109109?
The National Vulnerability Database rates CVE-2026-109109 as a CVSS 10 critical severity vulnerability.
Which Wavlink product is affected by this flaw?
The Wavlink WL-WN530BE1-A router running firmware version 251117 is the only affected system listed in the record.
Is there a patch available for this vulnerability?
The source material does not confirm the availability of a fix or update for this vulnerability at this time.
