# CVE-2025-51451: TOTOLINK EX1200T and N200RE authentication bypass in formLoginAuth.htm

Source: https://junglewise.ai/threats/cve-2025-51451-totolink-ex1200t-and-n200re-authentication-bypass-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-08-13. Updated: 2026-07-05  
License: CC BY 4.0 with a link back

CVE-2025-51451 · Severity: critical · CVSS 9.8 · Published 2025-08-13

A security vulnerability has been identified in TOTOLINK EX1200T and N200RE V5 routers that allows an unauthorized person to bypass the login screen. By sending a specially crafted web request, an attacker can gain full administrative access to the device without needing a password. This could lead to the theft of network data, unauthorized changes to internet settings, or a complete takeover of the home or office network.

Technologies: [TOTOLINK N200RE firmware](https://junglewise.ai/threats/technologies/n200re-firmware). Vendors: [TOTOLINK](https://junglewise.ai/threats/vendors/totolink).

## Quick answers

**Is CVE-2025-51451 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-51451 being exploited in the wild.

**How severe is CVE-2025-51451?** Critical severity, with a CVSS score of 9.8, published 13 August 2025.

**Which products and versions are affected?** TOTOLINK Ex1200t Firmware 4.1.2cu.5215; TOTOLINK N200RE firmware V9.3.5u.6139_B20201216.

**Is there a fix for CVE-2025-51451?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2025-51451 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2025-51451?** Check whether you run TOTOLINK Ex1200t, TOTOLINK Ex1200t Firmware or TOTOLINK N200RE firmware at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An authentication bypass vulnerability exists in the web management interface of TOTOLINK EX1200T (firmware 4.1.2cu.5215) and N200RE V5 (firmware V9.3.5u.6139_B20201216) routers. The flaw is located in the handling of requests to 'formLoginAuth.htm', where improper authentication logic allows a remote, unauthenticated attacker to bypass the login process. By sending a specifically crafted HTTP request to this endpoint, an attacker can gain full administrative privileges over the device. This is categorized as CWE-287 (Improper Authentication). While the advisory mentions specific firmware versions, users should check for updated firmware from the manufacturer as newer versions (e.g., V9.3.5u.6470 for N200RE) appear to address security concerns.

## Affected products

- TOTOLINK EX1200T firmware 4.1.2cu.5215
- TOTOLINK N200RE V5 firmware V9.3.5u.6139_B20201216

## Timeline

- 2025-08-13: advisory: Initial NVD publication date

## References

- [https://gist.github.com/lin-3-start/e42344d5caea881e5429fdd40fad1fd8](https://gist.github.com/lin-3-start/e42344d5caea881e5429fdd40fad1fd8)
- [https://www.totolink.net/home/menu/detail/menu_listtpl/download/id/204/ids/36.html](https://www.totolink.net/home/menu/detail/menu_listtpl/download/id/204/ids/36.html)

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