CVE-2026-76070
CVE-2026-76070
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 submitting an oversized Base64-encoded password to the login handler in /bin/netis.cgi. Attackers can exploit the custom Base64 decoder's lack of output length validation against the fixed-size stack buffer to achieve remote code execution with root privileges, as the Boa web server executes the CGI environment as root.
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: 0.013 (70.4th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 70th percentile — 70.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.010 · newest: 0.013 · change: +0.003
Weakness classification (CWE)
Public proof-of-concept exploits
References
- ozcanpng.dev/blog/cve-2026-76070-netis-nc63-login-stack-buffer-overflow/ (technical-description, exploit)
- github.com/ozcanpng/CVE-2026-76070 (technical-description, exploit)
- www.netis-systems.com/products/NC63.html (product)
- www.vulncheck.com/advisories/netis-nc63-stack-buffer-overflow-via-login-passwor… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-76070?
- CVE-2026-76070 is a critical-severity vulnerability, classified under Stack-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-08-24.
- How severe is CVE-2026-76070?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2026-76070 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.