According to the report, the security flaw in the world's third most popular browser is capable of allowing hackers and malicious sites to see a user's browsing history.
"The vulnerability could allow a malicious site to potentially determine which websites users have visited and have access to the URL or URL parameters," said Coates.
However, the company said that only a "limited number of users are affected".
Despite assuring users that there is "no indication that this vulnerability is currently being exploited in the wild", the company recommended that users downgrade to Firefox 15.0.1 until a fix was released, the report said.
Earlier this morning a patch was released for the mobile version of Firefox running on Android smartphones, following which an update was made available to Windows, Mac and Linux users of the desktop browser, Firefox 16.0.1. It is recommended that users upgrade immediately, the report added.