Vulnerability · Published Aug 24, 2026 · Assigned by VulnCheck
CVE-2026-76070Netis NC63 V3.0.0.3327 Stack Buffer Overflow via Login Password Parameter
Critical 9.8
In plain English
A critical-severity stack buffer overflow in NC63 from Netis Systems. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 1.3% (higher than 71% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Netis Systems | NC63 | 0 – through 3.0.0.3327 |
Weakness: CWE-121 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- Researcher Blog technical-description, exploit
- Researcher GitHub Repo technical-description, exploit
- Product Page product
- https://www.vulncheck.com/advisories/netis-nc63-stack-buffer-overflow-via-login-password-parameter third-party-advisory