CVE-2026-40854

Summary

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

Affected Software

VendorProductVersion RangeStatus
WNCT-Mobile 5G Box IDU0 < 1.1.0.651412affected

Weaknesses

  • CWE-290: CWE-290 Authentication bypass by spoofing

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: total

References