Extremely High CPU Usage from next-server in Production (Next.js 15.4.3)

[sayou]

Summary

Hi,

I’m experiencing very high CPU usage in production when running my Next.js app with next start. The issue began recently.

Environment

• Next.js Version: 15.4.3
• Node.js Version: 18.18.2
• PM2 Version: 5.3.0
• OS: Ubuntu 22.04
• Deployment Target: Self-hosted VPS
• Start Command: next start (managed by PM2)
• Package Manager: Yarn (berry)
• Build Command: NODE_ENV=production yarn build
• App Type: Custom app (not using Vercel)

Symptoms

After deployment, CPU usage spikes significantly:

PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
855183 appuser   20   0   31.7g 639880  61068 R 103.3   1.9   5:01.09 next-server

• No specific page or route causes this.
• No infinite loops or abnormal API polling detected.
• Behavior persists even when traffic is low.

CI/CD Context

Deployment is fully automated using GitHub Actions. Here’s a summary of what happens after a commit:

- name: Build
  run: NODE_ENV=production yarn build

- name: Deploy
  run: |
    rsync ./ to server
    ssh server '
      cd project &&
      yarn install --production &&
      pm2 restart "my-app"

'

Question

• What could cause next-server to consume 100%+ CPU in a typical production next start run?
• Are there any known regressions or debug flags I should use to trace this more deeply?
• Thanks for your help! Happy to share a minimal reproduction if needed.

Additional information

No response

Example

No response