It's an old crash report, from January 2016.

Try updating your firefox.

you can update following these steps

• Click the menu button , click help Help and select About Firefox.
• The About Firefox window will open and Firefox will begin checking for updates and downloading them automatically.

• When the updates are ready to be installed, click Restart Firefox to Update.

Important: If the update didn't start, didn't complete or there was some other problem, please use this download link or go to the Systems & Languages page to download and install the latest Firefox version for your system and language (see Install Firefox on Linux for instructions).

https://www.mozilla.org/en-US/firefox/new/?scene=2#download-fx