Security issues were identified and fixed in mozilla firefox and
thunderbird:

As more information has come to light about the attack on the DigiNotar
Certificate Authority we have improved the protections added in MFSA
2011-34. The main change is to add explicit distrust to the DigiNotar
root certificate and several intermediates. Removing the root as in
our previous fix meant the certificates could be considered valid if
cross-signed by another Certificate Authority. Importantly this list
of distrusted certificates includes the PKIOverheid (PKIGovernment)
intermediates under DigiNotar's control that did not chain to
DigiNotar's root and were not previously blocked.

Additionally, some packages which require so, have been rebuilt and
are being provided as updates.

Update:

Packages for Mandriva Linux 2011 is now being provided as well. Enjoy!