What’s new in Firefox 159?
Passwords saved in Firefox are available in the sidebar without you first having to enable the password tool in the sidebar. In other words, the sidebar password app is enabled by default—even if you don’t save your passwords in Firefox at all.
The AI-based Smart Window feature is designed to monitor websites for changes, such as new blog posts or price changes. This feature is being rolled out gradually, so it’s not yet available to all users.
Security vulnerabilities fixed in Firefox 159
In the security advisory for Firefox 159, Mozilla lists 167 security vulnerabilities that have been fixed. Of these, 65 were discovered and reported by external security researchers. Once again, Amy Burnett from OpenAI stands out with seven reports.
Mozilla classifies 108 vulnerabilities as high risk, 52 as medium risk, and seven as low risk. Among the fixed security vulnerabilities are 97 use-after-free (UAF) vulnerabilities, some of which could be suitable for injecting and executing malicious code. Thirteen vulnerabilities alone could be exploited to escape the browser’s sandbox.
Firefox ESR updates
In addition to Firefox 159.0, the ESR releases 153.6.0 and 115.44.0 are also available. However, the latter are only available for Windows 7 and 8.1 and macOS 10.12 to 10.14, and will remain so until March 2027.
In the ESR versions, Mozilla has fixed those of the above-mentioned vulnerabilities that are also present in the code of these older browser generations. That amounts to 145 vulnerabilities patched in Firefox 153.6.0 and 80 vulnerabilities in Firefox 115.44.