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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service
CVSS Vector v4.0
Weakness Type (CWE)
References 4
https://github.com/ozcanpng/CVE-2026-76071
disclosure@vulncheck.com
https://ozcanpng.dev/blog/cve-2026-76071-netis-nc63-ipfilter-stack-buffer-overf…
disclosure@vulncheck.com
https://www.netis-systems.com/products/NC63.html
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/netis-nc63-stack-buffer-overflow-via-desth…
disclosure@vulncheck.com