What is CVE-2026-76071?

CVE-2026-76071 is a critical-severity vulnerability in Netis Systems Nc63, classified under Stack-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-08-24.

How severe is CVE-2026-76071?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Netis Systems Nc63

CVE-2026-76071

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.

Vulnerability class: Buffer Overflow

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Netis Systems Nc63

Weakness classification (CWE)

CWE-121 — Stack-based Buffer Overflow

References

disclosure@vulncheck.com (technical-description, exploit)
disclosure@vulncheck.com (technical-description, exploit)
disclosure@vulncheck.com (product)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2026-76071?: CVE-2026-76071 is a critical-severity vulnerability in Netis Systems Nc63, classified under Stack-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-08-24.
How severe is CVE-2026-76071?: Critical severity. CVSS v3 base score is 9.8 out of 10.