CVE-2021-3304: Sagemcom F@st 3686 Firmware

Critical severity, CVSS 9.8. EPSS: 1.6% chance of exploitation in the next 30 days.

Sagemcom F@ST 3686 v2 3.495 devices have a buffer overflow via a long sessionKey to the goform/login URI.

Affected products

• Sagemcom F@st 3686 Firmware: version 3.495 only

Published 2021-01-26. Last modified 2026-06-17.