Firefox Security & Privacy Newsletter 2026 Q3

Security and privacy are core principles of Mozilla’s Manifesto and remain at the heart of Firefox’s development. This edition highlights key initiatives from Q3 2026 across three areas: Note: Some of the bugs linked below might not be accessible to the general public and restricted to specific work groups. We de-restrict fixed security bugs after a grace-period, until the majority of our user population have received Firefox updates.

If a link does not work for you, please accept this as a precaution for the safety of all Firefox users. Rapid Releases, Now Even Faster: Since September 2026, Firefox has followed a faster release cycle, bringing improvements, including security fixes, to users more quickly. We also invite you to see and shape what’s next for Firefox, including upcoming security and privacy features.

Many recent releases have included more security fixes. We continue to use frontier LLMs to identify and fix security bugs in Firefox to always keep you safe online.

Earlier coverage

• Product showcase: Sweet Virtual Patching stops HTTP2Shell while fixes catch up Nov 3
• Max-severity bug in widely used OT programming tool exploited to deliver Linux malware Nov 2
• next.js 16.4.4 released Nov 2