RHSA-2020:5239

Mozilla developers reported memory safety bugs present in Firefox 82 and Firefox ESR 78.4.

If the Compact() method was called on an nsTArray, the array could have been reallocated without updating other pointers, leading to a potential use-after-free and exploitable crash.

During browser shutdown, reference decrementing could have occured on a previously freed object, resulting in a use-after-free, memory corruption, and a potentially exploitable crash.

Some websites have a feature "Show Password" where clicking a button will change a password field into a textbook field, revealing the typed password.

When DNS over HTTPS is in use, it intentionally filters RFC1918 and related IP ranges from the responses as these do not make sense coming from a DoH resolver.

Firefox did not block execution of scripts with incorrect MIME types when the response was intercepted and cached through a ServiceWorker.

In some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS.

A parsing and event loading mismatch in Firefox's SVG code could have allowed load events to fire, even after sanitization.

Side-channel information leakage in graphics in Google Chrome prior to 87.0.4280.66 allowed a remote attacker to leak cross-origin data via a crafted HTML page.

It was possible to cause the browser to enter fullscreen mode without displaying the security UI; thus making it possible to attempt a phishing attack or otherwise confuse the user.