Related Vulnerabilities: CVE-2018-18497  

A security issue has been found in Firefox < 64.0, where limitations on the URIs allowed to WebExtensions by the browser.windows.create API can be bypassed when a pipe in the URL field is used within the extension to load multiple pages as a single argument. This could allow a malicious WebExtension to opened privileged about: or file: locations.

Severity Medium

Remote Yes

Type Access restriction bypass

Description

A security issue has been found in Firefox < 64.0, where limitations on the URIs allowed to WebExtensions by the browser.windows.create API can be bypassed when a pipe in the URL field is used within the extension to load multiple pages as a single argument. This could allow a malicious WebExtension to opened privileged about: or file: locations.

AVG-833 firefox 63.0.3-1 64.0-1 Critical Fixed

12 Dec 2018 ASA-201812-9 AVG-833 firefox Critical multiple issues

https://www.mozilla.org/en-US/security/advisories/mfsa2018-29/#CVE-2018-18497
https://bugzilla.mozilla.org/show_bug.cgi?id=1488180