CVE-2026-40857: CSRF

Description

WNC T-Mobile 5G Box IDU router contains a cross-site request forgery (CSRF) vulnerability in the portal.cgi component. The anti-CSRF mechanism fails to validate the csrf_token_value parameter, accepting any arbitrary value as valid. This allows a remote attacker to perform unauthorized actions on the device by tricking an authenticated user into visiting a malicious website.This issue has been fixed in firmware version 1.1.0.651412

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EPSS — Exploit Prediction

0.0020

Probability of exploitation

0.09%

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-352 Cross-Site Request Forgery

References

Other References

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

Frequently Asked Questions

What is CVE-2026-40857? +

WNC T-Mobile 5G Box IDU router contains a cross-site request forgery (CSRF) vulnerability in the portal.cgi component. The anti-CSRF mechanism fails to validate the csrf_token_value parameter, accepting any arbitrary value as valid. This allows a remote attacker to perform unauthorized actions on the device by tricking an authenticated user into visiting a malicious website.This issue has been fixed in firmware version 1.1.0.651412

How do I check if I'm vulnerable to CVE-2026-40857? +

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.

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