CVE-2026-40854

unknown

Assigned by CNA: cert-pl

Published 2026-09-16 · Modified 2026-09-16

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CVSS v3

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CVSS v4 NEW

8.7

CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

VIR risk

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Description

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

Predictions

Exploit likelihood

20%

Patch ETA

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Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

References

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

CWEs

CWE-290

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.