CVE-2026-40856: Missing Auth

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

Is your site exposed to CVE-2026-40856?

Run a free security scan — no signup, results in seconds.

EPSS — Exploit Prediction

0.0037

Probability of exploitation

0.30%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-306 Missing Authentication

References

Other References

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

Frequently Asked Questions

What is CVE-2026-40856? +

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

How do I check if I'm vulnerable to CVE-2026-40856? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-6369

An improper access control vulnerability in the canonical-livepatch snap client prior to version 10.15.0 allows a local unprivileged user to …

CVE-2026-9152

A missing authentication vulnerability exists in the Altium 365 SearchService. A legacy SOAP endpoint exposes search index operations without requiring …

CVE-2026-5749

Inadequate access control in the registration process in Fullstep V5, which could allow unauthenticated users to obtain a valid JWT …

CVE-2026-6376

A weakness in SpiceJet’s public booking retrieval page permits full passenger booking details to be accessed using only a PNR …

CVE-2024-45483

A Missing Authentication for Critical Function vulnerability in the GRUB configuration used B&R APROL <4.4-01 may allow an unauthenticated physical …

CVE-2024-54013

Penetration Testing engineers at Amazon have identified a security flaw related to request handling in the web server component that …