Mozilla has taken important steps to improve the browser experience with Firefox 136 version. The new update brought the vertical tabs that make the tab management more regular and a new side bar that provides more control within the browser. In addition, the Firefox 136 would maintain a large number of critical vulnerabilities by maintaining the sensitivity of security. Firefox EXTENDED SUPPORT REALEASE (ESR) and Tor Browser also benefited from this update. Mozilla said that users take into account the feedback on the closure of security vulnerabilities and to increase the overall performance of the browser.
According to the 2025-14 security consultancy report published by Mozilla, at least 15 security vulnerabilities were resolved with Firefox 136. Five of them contain critical problems reported by external security researchers and evaluated in the “high” risk category. In particular, the CV-2025-1930 coded security vulnerability stands out as a weakness that can cause overcoming the browser sandbox mechanism in Windows. Mozilla’s internal research was reported as a result of other critical weaknesses that could potentially lead to code execution or system collapse. However, Mozilla avoided giving comprehensive information about the full number and details of all the security deficits corrected.
Features that change the browser experience with Firefox 136 met with users
The side bar, which is offered with Firefox 136, is an innovation that makes the browser experience more flexible. Thanks to this side rod, users can easily access space -marks, past and tabs on other synchronized devices. In addition, if developers support, specific add -ons can also work in the side rod. The side rod can be placed on the right or left side of the screen depending on user preferences and offers a more useful experience thanks to these customization options.
The vertical tabs feature stands out as one of the remarkable innovations of the Firefox 136. Unlike the traditional horizontal tab sequence, when this feature is activated, tabs are lined up vertically in the side rod, not horizontally at the base of the browser window. This provides a better visibility and order for users who have opened many tabs. Especially those who are accustomed to the use of multiple tabs for business or academic studies may benefit from this innovation.
In addition, Mozilla has adopted a new approach that increases security with Firefox 136. Now the browser uses HTTPS-First mode by default. This provides access to websites and allows the use of a encrypted HTTPS protocol. If the HTTPS version is not available, the browser automatically returns to HTTP, but this process is performed to inform the user.
Mozilla has updated Firefox ESR 128 and ESR 115 with long -term supported versions of Firefox with security improvements. In the Firefox ESR 128.8.0 version, at least 10 vulnerabilities in Firefox ESR 115.21.0 were resolved. Parallel to this, Firefox ESR 128.8.0 -based Tor Browser was presented to users at 14.0.7. For users of Windows 7, 8.1 or MacOS 10.13 and 10.14, the Tor Browser 13.5.13 update was released.
Finally, Mozilla said Firefox ESR 115 will continue to be supported by at least September 2025. It was announced that the final decision regarding whether the life of this version will be extended will be made in the following months.