CVE-2026-111711CWE-121

CVE-2026-111711

Critical · published October 16, 2026

CVSS v3.1
9.8
EPSS
0%
Percentile
41.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
9.8 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
9.3 · 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
EPSS
0.00492 · 41.4th percentile
Weakness
CWE-121 · Stack-based Buffer Overflow
Published
2026-10-16T22:17Z
References (2)
https://github.com/lukadqq/netcore-router-public-refs/blob/a44d562736b41c944223297e9144d2ad7fa2aff1/2026.10.15-netcore-nr256cn-basic-auth-stack-overflow.md · [email protected]https://www.vulncheck.com/advisories/netcore-nr256cn-through-1.5.140116-pre-auth-stack-overflow-via-boa-user-ok · [email protected]
EPSS history
Timeline
  • 18 OCT 03:27Z
    EPSS moved — → 0%
    epss
  • 16 OCT 17:40Z
    Netcore NR256CN through 1.5.140116 Pre-Auth Stack Overflow via Boa user_ok()
    cvelistv5
  • 16 OCT 17:40Z
    Netcore NR256CN through 1.5.140116 Pre-Auth Stack Overflow via Boa user_ok()
    cvelistv5