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Fencer Intel
critical 9.3

CVE-2025-34117 in the critical feed json

Netcore / Netis Routers RCE via UDP Port 53413 Backdoor

published last yr. modified 4mo ago also EUVD-2025-21753

cvss
9.3
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
20.8%
EPSS 20.8% chance of exploitation in 30 days, percentile 97%
public exploits
1
Metasploit

Summary

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.

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Timeline

  1. First public exploit (Metasploit exploit/linux/misc/netcore_udp_53413_backdoor)
  2. Published

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
last yr.

Exploit prediction

20.77% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • Metasploit exploit/linux/misc/netcore_udp_53413_backdoor Netcore Router Udp 53413 Backdoor metasploit exploit, normal rank, 2014-08-25
  • raw.githubusercontent.com https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/exploits/linux/misc/netcore_udp_53413_backdoor.rb referenced PoC, tagged "exploit" by a source, unverified
  • vulners.com https://vulners.com/metasploit/MSF:EXPLOIT-LINUX-MISC-NETCORE_UDP_53413_BACKDOOR- referenced PoC, tagged "exploit" by a source, unverified
  • exploit-db.com https://www.exploit-db.com/exploits/43387 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 9.3 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
CNA 4.0 9.3 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/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

Affected products

  • Netcore Technology Router firmware
  • Netis Router firmware

Classification

Weakness
  • CWE-912 Hidden Functionality
  • CWE-306 Missing Authentication for Critical Functionality
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.