ElectronNET/Electron.NET

No port protection if application is launched twiced

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#971 opened on Dec 8, 2025

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bugenhancementhelp wanted

Description

  • Version: 13.5.1 (but confirmed source code was not improved in the latest for this issue)
  • Target: Windows (Windows 11) / MacOS (M Series)

What is happening is that during app startup, Electron Dot Net will inspect open ports to use as a setting for spawning the back-end server. There is a brief window between when the port number is selected, and when the back-end app actually starts up to utilize that port. If another app were to also start up during this time, then you get multiple instances attempting to spawn a back-end server using that same port and configuration. This results in a collision of port usage, causing the app to either crash or lock up.

Steps to Reproduce:

  1. Launch built electron dot net application
  2. Quickly launch a second instance
  3. Note JavaScript exception that appears

Contributor guide

Tech stack
csharpelectronnodejs
Domain
desktopbackend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Basic understanding of Electron.NETFamiliarity with port allocation
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
45
Research direction
Investigate the port selection mechanism in Electron.NET's startup code (likely in the ElectronHost or program entry). Examine the race condition where two instances pick the same port before binding. Consider using a lock or atomic port allocation. Check if there is a mutex or single instance enforcement already; if not, propose adding one.