Security Vulnerabilities fixed in Firefox 81

2020-09-22T00:00:00
ID MFSA2020-42
Type mozilla
Reporter Mozilla Foundation
Modified 2020-09-22T00:00:00

Description

When processing surfaces, the lifetime may outlive a persistent buffer leading to memory corruption and a potentially exploitable crash. By exploiting an Open Redirect vulnerability on a website, an attacker could have spoofed the site displayed in the download file dialog to show the original site (the one suffering from the open redirect) rather than the site the file was actually downloaded from. Firefox sometimes ran the onload handler for SVG elements that the DOM sanitizer decided to remove, resulting in JavaScript being executed after pasting attacker-controlled data into a contenteditable element. When recursing through graphical layers while scrolling, an iterator may have become invalid, resulting in a potential use-after-free. This occurs because the function APZCTreeManager::ComputeClippedCompositionBounds did not follow iterator invalidation rules. Mozilla developer Jason Kratzer reported memory safety bugs present in Firefox 80 and Firefox ESR 78.2. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. Mozilla developers Byron Campen and Christian Holler reported memory safety bugs present in Firefox 80. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.