Red Hat: CVE-2020-26951: CVE-2020-26951 Mozilla: Parsing mismatches could confuse and bypass security sanitizer for chrome privileged code (Multiple Advisories)

A parsing and event loading mismatch in Firefox's SVG code could have allowed load events to fire, even after sanitization. An attacker already capable of exploiting an XSS vulnerability in privileged internal pages could have used this attack to bypass our built-in sanitizer. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.