CVE-2026-111711
Deferred Deferred - Pending Action

Netcore NR256CN Pre-Authentication Stack Overflow via Boa Web Server

Publication date: 2026-10-16

Last updated on: 2026-10-16

Assigner: VulnCheck

Description
Netcore NR256CN through 1.5.140116 contains a pre-authentication stack overflow vulnerability in the Boa web server's user_ok() function, which copies Basic-auth usernames with unbounded strcpy() calls into 64-byte stack buffers. Unauthenticated attackers can send a username longer than 63 bytes to any protected /router/*.cgi route to crash the main Boa process or potentially execute code.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-10-16
Last Modified
2026-10-16
Generated
2026-10-19
AI Q&A
2026-10-16
EPSS Evaluated
2026-10-18
NVD
CVE-2026-111711
EUVD
EUVD-2026-103003

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
Netcore NR256CN 0

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-121 A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

Netcore NR256CN through version 1.5.140116 has a pre-authentication stack overflow in the Boa web server's user_ok() function. It uses unsafe strcpy() calls to copy Basic-auth usernames into 64-byte stack buffers without length checks. Attackers can exploit this by sending a username longer than 63 bytes to any /router/*.cgi route, causing the Boa process to crash or potentially execute arbitrary code.

Detection Guidance

To detect this vulnerability, scan for Netcore NR256CN devices running Boa web server versions through 1.5.140116. Check for exposed /router/*.cgi routes and test with long usernames (over 63 bytes) to trigger potential crashes or code execution. Use network scanners like Nmap to identify vulnerable devices.

Impact Analysis

Unauthenticated attackers could crash the Boa web server, leading to denial of service. In worst cases, they might execute arbitrary code on the device, gaining full control. This could allow unauthorized access to network resources, data theft, or further compromise of connected systems.

Compliance Impact

This vulnerability could lead to unauthorized access or data breaches, violating confidentiality requirements in GDPR and HIPAA. Organizations using affected Netcore NR256CN devices may face compliance violations, legal penalties, and reputational damage due to potential exposure of sensitive data.

Mitigation Strategies

Immediately update Netcore NR256CN to the latest firmware beyond version 1.5.140116. If no update is available, restrict access to /router/*.cgi routes via firewall rules, disable Basic-authentication if possible, and monitor for unusual traffic patterns indicating exploitation attempts.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-111711. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart