Security Advisory: Multiple Remote Code Execution and Buffer Overflow Vulnerabilities

17th July 2026

On May 9, several potential security vulnerabilities were identified within the DrayTek VigorSwitch mainfunction.cgi component, including buffer overflow conditions and improper neutralization of special elements used in operating system commands.

Although these conditions have been confirmed to exist in the affected code, there are currently no known or documented methods to trigger or exploit them, and no practical attack path has been identified. Consequently, there is no evidence at this time that the reported issues are exploitable in deployed environments. If a viable exploitation method were identified, it would likely require an attacker to possess valid administrative credentials and be able to authenticate to the switch’s web management interface.

Should a method be identified that allows these conditions to be reached and successfully exploited, they could potentially result in arbitrary code execution on an affected appliance. However, the feasibility of such exploitation has not been demonstrated. Following coordinated disclosure with the Concordia University Security Research Centre (SRC), DrayTek Corp has addressed these findings in updated firmware releases and recommends that customers upgrade to the versions listed below as a preventive security measure.

Vulnerability Details

The firmware updates are released for the following models. No other models are affected. Please click here to download and upgrade the firmware for your specific model as soon as possible to ensure your system remains up to date.