CVE-2026-40855: Wnc T-Mobile 5g Box Idu

Critical severity, CVSS 9.3. EPSS: 1.6% chance of exploitation in the next 30 days.

WNC T-Mobile 5G Box IDU router is vulnerable to a command injection. The vulnerability exists in the ping functionality within the /cgi-bin/portal.cgi endpoint, specifically affecting the ping_ip, ping_size, and ping_times POST parameters. The root cause is the failure to verify and sanitize user-supplied input before incorporating it into a system command. This allows an authenticated attacker to execute arbitrary commands on the shell and gain root access to the system.This issue has been fixed in firmware version 1.1.0.651412

Affected products

• Wnc T-Mobile 5g Box Idu: before 1.1.0.651412 (fixed in 1.1.0.651412)

Published 2026-09-16. Last modified 2026-09-28.