Vulnerability · Published Sep 16, 2026 · Assigned by CERT-PL

CVE-2026-40856Config disclosure in T-Mobile 5G Box IDU routers

High 7.1

In plain English

A high-severity missing authentication in T-Mobile 5G Box IDU from WNC. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities).

Severity (CVSS 4.0)7.1High

Exploit odds (30 days)0.4%top 68.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

WNC T-Mobile 5G Box IDU router is vulnerable to improper access control. The vulnerability exists in the wnc_maccheck.cgi endpoint, which is accessible without authentication. It allows a remote attacker to retrieve sensitive configuration data, including the administrator web password, WiFi passphrase, and technical device information.This issue has been fixed in firmware version 1.1.0.651412

Affected products (as reported)

Vendor	Product	Versions
WNC	T-Mobile 5G Box IDU	0 – before 1.1.0.651412

Weakness: CWE-306 · Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

References

https://cert.pl/posts/2026/09/CVE-2026-40854