Friday, November 6, 2026

Firefox 63 Released with Enhanced Tracking Protection and Fixes 14 Security Vulnerabilities

Firefox 63 released with Fix for Security Vulnerabilities and enhanced tracking protection that lets to you block cookies and storage access from third-party trackers.

The feature more surgically targets the problem of cross-site tracking without the breakage and wide-scale ad blocking which occurred with our initial Tracking Protection implementation reads Mozilla blog post.

Firefox 63

Starting from the Firefox version 65 these protections to be enabled for all users by default.

The newly developed Enhanced Tracking Protection works by blocking the trackers based on the tracking protection list maintained by the disconnect. The classified trackers in the list are not able to access or set cookies, local storage, and other site data when loaded in a third-party context.

Firefox 63

Still, the tracking protection is available for the user who wants to opt-in to block all tracking loads.

Other Notable Improvements with Firefox 63 and Firefox ESR 60.3

Build an infrastructure of Firefox on Windows moved to Clang toolchain to improve performance.
New Theme based on Windows 10 OS Dark and Light modes
Improved reactivity and Faster tab switching for mac users
WebExtensions now run in their own process on Linux
Firefox now warns about having multiple windows and tabs open when quitting
Refreshed visual style of Developer Tools

Security Updates with Firefox 63

A number of security bugs in Firefox and Firefox ESR.

Firefox 63

CVE-2018-12390: Memory safety bugs fixed in Firefox 63
CVE-2018-12388: Memory safety bugs fixed in Firefox 63
CVE-2018-12391: HTTP Live Stream audio data is accessible cross-origin
CVE-2018-12392: Crash with nested event loops
CVE-2018-12393: Integer overflow during Unicode conversion while loading JavaScript
CVE-2018-12395: WebExtension bypass of domain restrictions through header rewriting
CVE-2018-12396: WebExtension content scripts can execute in disallowed contexts
CVE-2018-12397: Request access to local files without the warning prompt
CVE-2018-12398: CSP bypass through stylesheet injection in resource URIs
CVE-2018-12399: Spoofing of protocol registration notification bar
CVE-2018-12400: Favicons are cached in private browsing mode on Firefox for Android
CVE-2018-12401: DOS attack through special resource URI parsing
CVE-2018-12402: SameSite cookies leak when pages are explicitly saved
CVE-2018-12403: the Mixed content warning is not displayed when HTTPS page loads a favicon over HTTP

Firefox ESR 60.3

CVE-2018-12390: Memory safety bugs fixed in Firefox 63 and Firefox ESR 60.3
CVE-2018-12391: HTTP Live Stream audio data is accessible cross-origin
CVE-2018-12392: Crash with nested event loops
CVE-2018-12393: Integer overflow during Unicode conversion while loading JavaScript
CVE-2018-12395: WebExtension bypass of domain restrictions through header rewriting
CVE-2018-12396: WebExtension content scripts can execute in disallowed contexts
CVE-2018-12397: Request access to local files without the warning prompt
CVE-2018-12389: Memory safety bugs fixed in Firefox ESR 60.3
CVE-2018-12389: Memory safety bugs fixed in Firefox ESR 60.3

Related Read

Firefox, Chrome, Edge, and Safari To Disable TLS 1.0 and TLS 1.1 in 2020

Mozilla Firefox Releases 62.0.3 & Security Updates for 2 High Critical Vulnerabilities

Multiple Critical Vulnerabilities Fixed With Firefox 62 and Firefox ESR 60.2

Gurubaran
Gurubaran
Gurubaran is a co-founder of Cyber Security News and GBHackers On Security. He has 10+ years of experience as a Security Consultant, Editor, and Analyst in cybersecurity, technology, and communications.

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