CVE-2020-26951

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.

Recent assessments:

pbarry-r7 at November 19, 2020 5:44pm UTC reported:

Mozilla recently announced a fix for this vulnerability in Firefox 83. They marked this as Impact: high and provided the following details in their published advisory:

> 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.

The ability to bypass sanitization sounds like it’s worth Firefox users to patch to version 83.

Assessed Attacker Value: 0
Assessed Attacker Value: 0Assessed Attacker Value: 0