CVE-2026-40856: Config disclosure in T-Mobile 5G Box IDU routers
WNC T-Mobile 5G Box IDU router is vulnerable to improper access control. The vulnerability exists in the wncmaccheck.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 Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
WNC T-Mobile 5G Box IDU router firmwareto a version that resolves this vulnerability.Fixed in 1.1.0.651412 - Compensating control
Because the wnc_maccheck.cgi endpoint is accessible without authentication and allows remote retrieval of sensitive configuration (including the administrator web password and WiFi passphrase), restrict network access to the affected router/endpoint (e.g., block WAN access to the router web interface and endpoint) until firmware 1.1.0.651412 is applied.
Event History
Frequently Asked Questions
Who can exploit this issue?
A remote attacker can access the vulnerable wnc_maccheck.cgi endpoint without authentication. The exposed data includes the administrator web password, WiFi passphrase, and technical device information.
Which firmware version fixes the issue?
The issue has been fixed in firmware version 1.1.0.651412.