CVE-2025-34117: Netcore / Netis Routers RCE via UDP Port 53413 Backdoor

Vulnerability summary

CVE-2025-34117 is a critical (CVSS 9.3) vulnerability in netcore technology router firmware. EPSS estimates a 20.77% chance of exploitation in the next 30 days, higher than 97.5% of scored vulnerabilities. 4 public exploits are recorded.

Timeline

1. 16-07-2025
   PublishedVulnerability first disclosed.
2. 07-04-2026
   Last modifiedVulnerability information updated.

Description

A remote code execution vulnerability exists in multiple Netcore and Netis routers models with firmware released prior to August 2014 due to the presence of an undocumented backdoor listener on UDP port 53413. Exact version boundaries remain undocumented. An unauthenticated remote attacker can send specially crafted UDP packets to execute arbitrary commands on the affected device. This backdoor uses a hardcoded authentication mechanism and accepts shell commands post-authentication. Some device models include a non-standard implementation of the `echo` command, which may affect exploitability.

• CWE-78Improper Neutralization of Special Elements used in an OS CommandThe product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command before it is sent to a downstream component.
• CWE-306Missing Authentication for Critical FunctionalityThe product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
• CWE-912Hidden FunctionalityThe product contains functionality that is not documented, not part of the specification, and not accessible through an interface or command sequence that is obvious to the product's users or administrators.