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 4.0

9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

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

EPSS

1.3% chance of exploitation in the next 30 days; higher than 71% of CVEs (scores of 2026-10-25)

CWE

CWE-121

Published

2026-08-24

Modified

2026-10-12

Record from

the NVD, synced 2026-10-19

References

• https://github.com/ozcanpng/CVE-2026-76070
• https://ozcanpng.dev/blog/cve-2026-76070-netis-nc63-login-stack-buffer-overflow/
• https://www.netis-systems.com/products/NC63.html
• https://www.vulncheck.com/advisories/netis-nc63-stack-buffer-overflow-via-login-password-parameter

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