Firefox 158 adds AI form filling and fixes 77 security flaws

Mozilla released Firefox 158 for Windows, macOS, Linux and Android with an AI-powered Smart Windows feature for automatic form filling and support for the JPEG XL image format. The update patches 77 security flaws, including 30 high-risk ones, 24 of which could allow malicious code execution. Firefox 159 is scheduled for October 27, 2026.

• 77 security flaws fixed, 30 rated high risk
• 24 use-after-free bugs could run malicious code
• 8 vulnerabilities allowed escaping the browser sandbox
• Adds JPEG XL support and better PDF saving