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.

CVSS v4.0

9.3 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1

9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

1.00% chance of exploitation in the next 30 days, 60th percentile

Published

2026-08-24

Proof-of-concept exploits (2)

• https://ozcanpng.dev/blog/cve-2026-76070-netis-nc63-login-stack-buffer-overflow/
• ozcanpng/CVE-2026-760701★ · 2026-08-19

References

• CVE Record
• NVD entry

Related

• CVE-2023-34468
• CVE-2024-9264
• CVE-2025-57819
• CVE-2025-60787
• CVE-2026-23744
• CVE-2026-73673