SQL injection vulnerability in Quassel IRC before 0.9.1, when Qt 4.8.5 or later and PostgreSQL 8.2 or later are used, allows remote attackers to execute arbitrary SQL commands via a \ (backslash) in a message.
The CtcpParser::packedReply method in core/ctcpparser.cpp in Quassel before 0.7.3 allows remote attackers to cause a denial of service (crash) via a crafted Client-To-Client Protocol (CTCP) request, as demonstrated in the wild in September 2011.