Critical 9.8Published Oct 16, 2026

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

Updated under an hour ago (Oct 28, 2026, 10:50 AM ET)

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It affects Netcore NR256CN. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.49%, higher than 42% of scored CVEs.

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Every CVE for Netcore NR256CN

Exploited in the last 30 days

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: 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-121
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.49% (percentile 42)
Assigned by: VulnCheck
NVD analysis: Deferred
Record last updated: Oct 16, 2026
First seen by InfoSec Signals: Oct 16, 2026

Affected products

Affected products

Netcore NR256CN netcore:nr256cn (from the name)	through 1.5.140116	CNA record

References

References

https://github.com/lukadqq/netcore-router-public-refs/blob/a44d562736b41c944223297e9144d2ad7fa2aff1/2026.10.15-netcore-nr256cn-basic-auth-stack-overflow.md	third-party-advisory
https://www.vulncheck.com/advisories/netcore-nr256cn-through-1.5.140116-pre-auth-stack-overflow-via-boa-user-ok	third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.