https://blog.freenode.net/2014/09/server-issues-2
Server issues
Posted on 2014-09-13 by mrmist
Earlier today the freenode infra team noticed an anomaly on a
single IRC server. We have since identified that this was indicative of
the server being compromised by an unknown third party. We immediately
started an investigation to map the extent of the problem and located
similar issues with several other machines and have taken those offline.
For now, since network traffic may have been sniffed, we recommend that
everyone change their NickServ password as a precaution.
To change your password use /msg nickserv set password newpasshere
Since traffic may have been sniffed, you may also wish to consider
any channel keys or similar secret information exchanged over the
network.
We’ll issue more updates as WALLOPS and via social media!