CVE-2017-18046: Dasannetworks h640x Firmware

Critical severity, CVSS 9.8. EPSS: 5% chance of exploitation in the next 30 days.

Buffer overflow on Dasan GPON ONT WiFi Router H640X 12.02-01121 2.77p1-1124 and 3.03p2-1146 devices allows remote attackers to execute arbitrary code via a long POST request to the login_action function in /cgi-bin/login_action.cgi (aka cgipage.cgi).

Affected products

• Dasannetworks h640x Firmware: version 2.77p1-1124 only; version 3.03p2-1146 only; version 12.02-01121 only

Published 2018-01-21. Last modified 2026-06-17.