znc.cpp in ZNC before 0.092 allows remote authenticated users to cause a denial of service (crash) by requesting traffic statistics when there is an active unauthenticated connection, which triggers a NULL pointer dereference, as demonstrated using (1) a traffic link in the web administration pages or (2) the traffic command in the /znc shell.

Directory traversal vulnerability in ZNC before 0.072 allows remote attackers to overwrite arbitrary files via a crafted DCC SEND request.

Multiple CRLF injection vulnerabilities in webadmin in ZNC before 0.066 allow remote authenticated users to modify the znc.conf configuration file and gain privileges via CRLF sequences in the quit message and other vectors.