CVE-2026-76071: Netis Systems NC63

Critical severity, CVSS 9.8. EPSS: 1.4% chance of exploitation in the next 30 days.

Netis NC63 firmware through V3.0.0.3327 contains a stack-based buffer overflow vulnerability that allows unauthenticated remote attackers to overwrite saved stack state by supplying an oversized destHost parameter to the ipFilterList=mod action in netis.cgi. Attackers can exploit widthless sscanf conversions that copy user-supplied input into fixed-size stack buffers before authentication is verified, achieving remote code execution as root due to the Boa web server executing the CGI environment with root privileges.

Affected products

• Netis Systems NC63: up to and including 3.0.0.3327

Published 2026-08-24. Last modified 2026-09-24.