---
id: CVE-2026-76070
title: >-
  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
  hand…
summary: >-
  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
  hand…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-121
published: '2026-08-24'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T20:43:32.537'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-76070'
references:
  - url: 'https://github.com/ozcanpng/CVE-2026-76070'
    label: disclosure@vulncheck.com
  - url: >-
      https://ozcanpng.dev/blog/cve-2026-76070-netis-nc63-login-stack-buffer-overflow/
    label: disclosure@vulncheck.com
  - url: 'https://www.netis-systems.com/products/NC63.html'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/netis-nc63-stack-buffer-overflow-via-login-password-parameter
    label: disclosure@vulncheck.com
tags:
  - nvd
  - exploit-available
epss: 0.01338
epssPercentile: 0.7006
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/ozcanpng/CVE-2026-76070'
  checkedAt: '2026-09-26T09:05:59.961Z'
exploitAvailable: true
ingestedAt: '2026-09-24T20:51:40.223Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.