[ubuntu] Can web browser extensions infect Linux?

So, as a long term Linux user I should probably already know the answer to this, but I installed a couple of addons in Firefox and Chrome. I was wondering if it was possible that assuming 1 of those addons were malicious, could it infect my linux distro?

Assuming one of the addons were malicious, could it access my /home/useame? Could it steal passwords I input on Palemoon (my browser of choice)?

Thanks!