CVE-2026-111711 PUBLISHED

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

Assigner: VulnCheck
Reserved: 16.10.2026 Published: 16.10.2026 Updated: 16.10.2026

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 Vector: CVSS: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 Score: 9.3

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

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

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	High
Privileges Required	None	Integrity Impact	High
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	Netcore
Product	NR256CN
Versions	Default: unaffected affected from 0 to 1.5.140116 (incl.)

CVE-2026-111711 PUBLISHED

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

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Product Status

Credits

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Problem Types