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
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.014 (72.0th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 72nd percentile — 72.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.011 · newest: 0.014 · change: +0.004
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- ozcanpng.dev/blog/cve-2026-76071-netis-nc63-ipfilter-stack-buffer-overflow/ (technical-description, exploit)
- github.com/ozcanpng/CVE-2026-76071 (technical-description, exploit)
- www.netis-systems.com/products/NC63.html (product)
- www.vulncheck.com/advisories/netis-nc63-stack-buffer-overflow-via-desthost-para… (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.
- Is CVE-2026-76071 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.