A vulnerability in the Pix-Link LV-WR21Q router's language module allows remote attackers to trigger a denial of service (DoS) by sending a specially crafted HTTP POST request containing non-existing language parameter. This renders the server unable to serve correct lang.js file, which causes administrator panel to not work, resulting in DoS until the language settings is reverted to a correct value. The Denial of Service affects only the administrator panel and does not affect other router functionalities. The vendor was notified early about this vulnerability, but didn't respond with the details of vulnerability or vulnerable version range. Only version V108_108 was tested and confirmed as vulnerable, other versions were not tested and might also be vulnerable.