Zen Browser 1.21.16b has been released, featuring performance optimizations and security enhancements based on Firefox 154.0.1. The update improves session store operations, reduces CPU spikes, and resolves bugs related to password storage and Picture-in-Picture functionality. It also addresses over 50 high-impact vulnerabilities as outlined in Mozilla's MFSA-2026-74 advisory. The project, maintained by a single developer, continues to rapidly release updates, garnering significant community support while maintaining a focus on open-source principles
Zen Browser 1.21.16b Released: Firefox 154 Security Patches and Session Store Fixes
Zen Browser 1.21.16b has arrived, riding on Firefox 154.0.1 to deliver critical performance optimizations and security hardening to the open-source Firefox fork. The update focuses primarily on smoothing out session store operations, significantly reducing CPU spikes and disk I/O when saving open tabs, while also squashing lingering bugs like a persistent password storage regression and broken Picture-in-Picture sidebar collapsing. By integrating Mozilla's MFSA-2026-74 advisory, the build addresses over 50 high-impact vulnerabilities, including sandbox escapes and privilege escalation flaws, without sacrificing the project's rapid release cadence.
