Stack-Based Buffer Overflow Vulnerability in Netis NC63 Firmware
CVE-2026-76071

9.3CRITICAL

Key Information:

Vendor

Netis Systems

Status
Nc63
Vendor
CVE Published:
24 August 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-76071?

The Netis NC63 firmware versions up to V3.0.0.3327 exhibits a vulnerability where unauthenticated remote attackers can exploit a stack-based buffer overflow by providing an oversized 'destHost' parameter in a specific CGI action. This vulnerability allows attackers to manipulate the stack state, potentially leading to remote code execution with root privileges due to the Boa web server operating the CGI environment at a privileged level. This flaw underscores the need for careful input validation and security measures in firmware development.

Affected Version(s)

NC63 0 <= 3.0.0.3327

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-76071 - Proof of Concept

CVE-2026-76071
Created by ozcanpng

References

https://ozcanpng.dev/blog/cve-2026-76071-netis-nc63-ipfil...
technical-descriptionexploit
https://github.com/ozcanpng/CVE-2026-76071
technical-descriptionexploit
https://www.netis-systems.com/products/NC63.html
product

CVSS V4

Score:
9.3
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Özcan Ersan (@ozcanpng)
.