Firefox Suffers Massive Extension Outage Due to Expired Certificate
Mozilla Firefox experiences a widespread extension failure, known as "armagadd-on," after an intermediate signing certificate unexpectedly expires. The company resolves the issue in 12 hours and vows to improve its security processes.
Mozilla Firefox experiences a sudden, widespread outage that disables all browser add-ons, an event the internet dubs "armagadd-on." The issue stems from an expired intermediate security certificate that Firefox uses to verify and sign third-party extensions. Because the browser checks certificate validity every 24 hours, different users lose access to their add-ons at different times rather than all at once.
Firebase Chief Technology Officer Eric Rescorla catches the problem around 6 p.m. PT on May 3, and it takes the team roughly 12 hours to fully restore functionality. Re-signing all 15,000-plus add-ons manually is impossible due to the sheer volume, so engineers instead deploy a patch to bypass the expiration check. This fix allows users to regain access to their ad-blockers, password managers, and other essential tools.
Mozilla openly admits that the embarrassing glitch should never have occurred and publishes a detailed postmortem about the incident. The company now treats the armagadd-on disaster as a crucial learning lesson to adjust its internal processes. Moving forward, Firefox aims to implement safeguards that prevent similar certificate expirations and make future fixes much faster to deploy.