cache/mozilla/firefox/3kcsx76o.default/Cache/C/66/C41D9d01      PUA.Html.Trojan.Agent-37075

I did a fresh install of Ubuntu 14.04.1 on my HP Pavilion G6 laptop. I installed ClamTK antivirus app, and ran it. There were no Possible Undesirable Applications (PUA's) were found. Notified that my older version of Firefox was no longer supported, I used the Software Updater to update my laptop. I ran ClamTK immediately again after the Firefox (and other) upgrades from the Ubuntu repository and found a Trojan Horse existed in Firefox. Details are given in the screenshot of the ClamTK results. I uninstalled Firefox and reinstalled it and ran ClamTK again. No PUA's were found. What is up with Firefox's commitment to safe internet browsing if a trojan agent is found in a Firefox upgrade? Details of the trojan agent found by ClamTK are given below: cache/mozilla/firefox/3kcsx76o.default/Cache/C/66/C41D9d01 PUA.Html.Trojan.Agent-37075