Related Vulnerabilities: CVE-2020-16012  

A parsing and event loading mismatch has been found in Firefox's SVG code before 83.0 and 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 the built-in sanitizer.

Severity High

Remote Yes

Type Access restriction bypass

Description

A parsing and event loading mismatch has been found in Firefox's SVG code before 83.0 and 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 the built-in sanitizer.

AVG-1279 firefox 82.0.3-1 83.0-1 Critical Fixed

https://www.mozilla.org/en-US/security/advisories/mfsa2020-50/#CVE-2020-26951
https://bugzilla.mozilla.org/show_bug.cgi?id=1667113