Vulnerability · Published Oct 16, 2026 · Assigned by VulnCheck

CVE-2026-111711Netcore NR256CN through 1.5.140116 Pre-Auth Stack Overflow via Boa user_ok()

Critical 9.8

In plain English

A critical-severity stack buffer overflow in NR256CN from Netcore. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities).

Severity (CVSS 3.1)9.8Critical

Exploit odds (30 days)0.5%top 57.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
Netcore	NR256CN	0 – through 1.5.140116

Weakness: CWE-121 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

In plain English

Official description

Affected products (as reported)

References