https://support.mozilla.org/en-US/kb/keep-flash-up-to-date-and-troubleshoot-problems You can try to keep it updated from appropriate repository in your package manager of your Linux distro. Or you can download from Adobe at https://get.adobe.com/flashplayer/ I prefer to use the tar.gz and put the libflashplayer.so in created '''plugins''' folder in /home/username/.mozilla/plugins/ Downside is you have to manually add each new version this way.