CVE-2026-40854Session auth bypass via cookie value in T-Mobile 5G Box IDU routers
Updated under an hour ago ()
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It affects WNC T-Mobile 5G Box IDU. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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
- CVSS
- 8.7 HIGH (v4.0, CNA)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
- Weakness (CWE)
- CWE-290
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- CERT-PL
- NVD analysis
- Awaiting Analysis
- Record last updated
- Sep 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
WNC T-Mobile 5G Box IDU wnc:t_mobile_5g_box_idu (from the name) | before 1.1.0.651412 | CNA record |
References
- https://cert.pl/posts/2026/09/CVE-2026-40854third-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.