Firefox 159 fixes 167 security bugs as Chrome patches 52 flaws
Firefox 159 addresses 108 high-severity bugs and multiple use-after-free flaws; Chrome's update fixes four critical issues in Windows, Mac and Linux builds.
Mozilla released Firefox 159 for Windows, Android, MacOS and Linux on October 29, 2026, fixing 167 security bugs, 108 of which were rated high severity, according to ZDNET. Many of the fixes address use-after-free memory vulnerabilities and Sandbox issues.
Google also shipped new Chrome builds: version 56.0.8078.73/.74 for Windows and Mac and 156.0.8078.73 for Linux. The update patches 52 security bugs, four rated critical and 46 rated high.
The four critical Chrome flaws involve memory corruption and a Sandbox bypass.
Mozilla credited Amy Burnett, a security researcher at OpenAI, for uncovering many of the Firefox bugs. Google attributed the discovery of several Chrome flaws to Anthropic's Claude and a few to OpenAI.
Firefox 159 also brings smaller changes: on Mac, the browser now shows the built-in MacOS share picker when sharing a page, and a passwords tool is available in the sidebar. The browser's AI-powered Smart Window can now monitor a web page and notify users of changes through the /watch command.
Quick answers
What does Firefox 159 fix?
Firefox 159 fixes 167 security bugs, including 108 rated high severity, many of them use-after-free memory vulnerabilities and Sandbox issues.
What version of Chrome is the latest security update?
Google released Chrome 56.0.8078.73/.74 for Windows and Mac and 156.0.8078.73 for Linux, patching 52 security bugs.
What is the /watch command in Firefox?
It is a command for Firefox's AI-powered Smart Window that lets the browser monitor a web page and notify users of changes.