Attackers could slip malware into Firefox and Thunderbird and thus execute their own commands on systems. Overall, the risk from the security vulnerabilities is considered ” high “.

Mozilla not only closed loopholes, but also built in a function to increase security when surfing with Firefox – which, however, is not active in the standard setting. The versions Firefox 83 , Firefox ESR 78. 5 and Thunderbird 78. 5 for all systems.

Closed security holes in Thunderbird 78. 5 Closed vulnerabilities in Firefox ESR 78. 5 Closed vulnerabilities in Firefox 83 Only surf encrypted In Firefox 83 is now available in an HTTPS-only mode. If this mode is active, the web browser always establishes an encrypted connection via HTTPS to websites. This happens automatically, for example, if you enter a URL starting with HTTP or click on an HTTP link.

If a website does not support HTTPS, Firefox displays a warning that third parties may visit such sites of users entering credit card information. Anyone who is aware of the risk can still visit such sites. HTTPS-only is then temporarily deactivated for the page. In some cases, websites reload resources via HTTP (mixed content). In such cases, there may be display errors on Internet pages.

Activate HTTPS-only To use the HTTPS-only mode, you have to activate it in the Firefox settings under “Data protection & security” at the bottom. If desired, the mode can be used in all windows or only in private windows. If HTTPS-only causes problems on a page, you can deactivate it by clicking on the lock symbol in the address bar.

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