Heroku outage, 10 June 2025

Heroku platform outage from unintended OS update (10 June 2025). The disruption lasted about 23 hours 16 minutes, according to Heroku’s own timeline.

What happened. An automated operating-system update ran on production hosts when it should have been disabled, restarting networking services. A legacy script only applied routing rules at first boot, so routes weren’t reapplied and dynos lost outbound connectivity; Heroku’s own tools and status page ran on the same infrastructure.

What changes. Heroku disabled the automated upgrade service, will allow no system changes outside its controlled deployment process, audited base images, and made networking handle graceful restarts.

Questions

What caused the Heroku outage in June 2025?

An automated operating-system update ran on production hosts when it should have been disabled, restarting networking services.

Which services were affected?

Heroku apps/dynos (esp. Private Spaces), Heroku Dashboard, Heroku Status Page, internal tooling.

Read how shared dependencies spread a failure in why one cloud outage can break unrelated apps, or browse the outage archive.