# CVE-2026-36959: U-SPEED N300 missing rate limiting in /api/login

Source: https://junglewise.ai/threats/cve-2026-36959-u-speed-n300-missing-rate-limiting-in-api-login  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-30. Updated: 2026-07-05  
License: CC BY 4.0 with a link back

CVE-2026-36959 · Severity: high · CVSS 7.5 · Published 2026-04-30

The U-SPEED N300 router fails to limit the number of times a user can attempt to log in to the management interface. This allows an attacker to repeatedly guess the administrator password without being blocked or slowed down. If successful, an attacker could gain full control over the router's settings and the traffic passing through the network.

Vendors: [U-SPEED](https://junglewise.ai/threats/vendors/u-speed).

## Quick answers

**Is CVE-2026-36959 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-36959 being exploited in the wild.

**How severe is CVE-2026-36959?** High severity, with a CVSS score of 7.5, published 30 April 2026.

**Which products and versions are affected?** U-SPEED N300 Router 1.0.0.

**Is there a fix for CVE-2026-36959?** 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-2026-36959 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-36959?** Check whether you run U-SPEED N300, U-SPEED N300 Router or U-SPEED N300 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

The U-SPEED N300 router firmware version 1.0.0 contains a vulnerability classified as CWE-307 (Improper Restriction of Excessive Authentication Attempts). The /api/login endpoint lacks rate limiting, exponential backoff, or account lockout mechanisms. A network-based attacker can send an unlimited number of POST requests to the authentication API to brute-force administrative credentials. Successful exploitation grants the attacker unauthorized administrative access to the router management interface, potentially leading to full device compromise. As of the advisory date, no official patch has been confirmed, though remediation steps include implementing throttling or CAPTCHA.

## Affected products

- U-SPEED N300 Router 1.0.0

## Timeline

- 2026-04-29: disclosed: Vulnerability discovered and reported to MITRE
- 2026-04-30: advisory: NVD publication date

## References

- [https://github.com/kirubel-cve/CVE-2026-36959](https://github.com/kirubel-cve/CVE-2026-36959)

## Related threats

- [U-SPEED N300 Router CSRF in web management interface](https://junglewise.ai/threats/cve-2026-36960-u-speed-n300-router-csrf-in-web-management-interface)
- [U-SPEED N300 resource exhaustion DoS in Boa HTTP server](https://junglewise.ai/threats/cve-2026-36958-u-speed-n300-resource-exhaustion-dos-in-boa-http-server)