by Kastro
Paper/Archive/CVE-2026-40855

CVE-2026-40855

WNC T-Mobile 5G Box IDU — Command Injection in T-Mobile 5G Box IDU router via ping functionality

EPSS 2%CVSS 9.3
critical.is priorityof 100
43
CVSS 9.3 (CNA)9.3 / 10 × 3027.9Not in CISA KEV+300.0EPSS percentile 75.7.757 × 2015.1No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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

ProductAffectedFixed inSource
T-Mobile 5G Box IDU< 1.1.0.6514121.1.0.651412CNA

Scores by source

CERT-PL (CNA)9.3CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: total

References

writeupcert.pl/posts/2026/09/CVE-2026-40854