CVE-2026-40854

UNKNOWN 0.0

Session auth bypass via cookie value in T-Mobile 5G Box IDU routers

CVSS Score

0.0

EPSS Score

0.0%

EPSS Percentile

0th

WNC T-Mobile 5G Box IDU router contains an authentication bypass vulnerability in the portal.cgi component. The session verification mechanism improperly validates the sessionid cookie by checking for the existence of a corresponding file in /tmp/login_user. An attacker can bypass authentication by using directory entries such as "." or ".." in the cookie, allowing unauthorized access to the administration panel.This issue has been fixed in firmware version 1.1.0.651412

CWE	CWE-290
Vendor	wnc
Product	t-mobile 5g box idu
Published	Sep 16, 2026

Stay Ahead of the Next One

Get instant alerts for wnc t-mobile 5g box idu

Be the first to know when new unknown vulnerabilities affecting wnc t-mobile 5g box idu are published — delivered to Slack, Telegram or Discord.

Get Free Alerts → Free · No credit card · 60 sec setup

Affected Versions

WNC / T-Mobile 5G Box IDU

0 < 1.1.0.651412

References

NVD ↗ CVE.org ↗ EPSS Data ↗

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

Credits

Patryk Bogdan Adam Borczyk