T-Mobile 5G Box IDU: Cross-Site Request Forgery
CVE-2026-40857 is a high-severity cross-site request forgery vulnerability in T-Mobile 5G Box IDU from WNC, with a CVSS 4.0 base score of 8.4 out of 10. It can be exploited from the same local network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version 1.1.0.651412 as the first without the flaw, so updating T-Mobile 5G Box IDU to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.2% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update T-Mobile 5G Box IDU to 1.1.0.651412 or a later version.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| WNC | T-Mobile 5G Box IDU | before 1.1.0.651412 | 1.1.0.651412 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- AdjacentThe attacker must be on the same local network segment.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Attack requirements
- NoneThe attack does not depend on a particular deployment or configuration.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- ActiveA user must deliberately do something unusual, such as dismissing a warning.
- Confidentiality (vulnerable system)
- HighSerious loss of confidentiality on the vulnerable system.
- Integrity (vulnerable system)
- HighSerious loss of integrity on the vulnerable system.
- Availability (vulnerable system)
- LowLimited loss of availability on the vulnerable system.
- Confidentiality (other systems)
- NoneNo loss of confidentiality on systems beyond the vulnerable one.
- Integrity (other systems)
- NoneNo loss of integrity on systems beyond the vulnerable one.
- Availability (other systems)
- NoneNo loss of availability on systems beyond the vulnerable one.
Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA (cert.pl).
Official 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
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Cross-Site Request Forgery
The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.
How developers prevent this class of flaw
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, use anti-CSRF packages such as the OWASP CSRFGuard. Another example is the ESAPI Session Management control, which includes a component for CSRF.
- Ensure that the application is free of cross-site scripting issues (CWE-79), because most CSRF defenses can be bypassed using attacker-controlled script.
- Generate a unique nonce for each form, place the nonce into the form, and verify the nonce upon receipt of the form. Be sure that the nonce is not predictable (CWE-330).
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in T-Mobile 5G Box IDU
- 9.3 Critical severity
- 9.4 Critical severity
- 7.1 High severity
- 9.3 Critical severity
- 8.7 High severity
Recent Cross-Site Request Forgery vulnerabilities
- 7.1 High severity
- 8.1 High severity
- 8.1 High severity
- 8.1 High severity
- 8.6 High severity
- 8.1 High severity
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