Comment 28 for bug 855171

@Vladimir: as the summary states (although the :i386 version is unneeded), you need to do:

sudo apt-get install --reinstall libnss3

The problem is that ca-certificates has removed files from libnss3, so even if libnss3 reports itself as installed you will need to reinstall it in order to recover the missing files. With a bit of luck, you will have libnss3 in /var/cache/apt, and the above command won't need an internet connection to complete successfully - else you will need to configure your connection from the command line, or fetch the package on a second computer and copy it to the affected system using a physical storage device.

Afterwards, update your ca-certificates to a working version.