From the Register:
The discovery of a trio of security bugs means that users of the popular Trillian instant messaging client need to update their software.
All three of the newly discovered bugs create a means for hackers to inject malware onto the PCs of surfers running vulnerable versions of the multi-protocol chat application from Cerulean Studios. The vulnerabilities involve flaws in how Trillian parses MSN protocol traffic, an error within XML parsing, and a third flaw involving the processing of messages with long (malformed) attribute values within the FONT tag can be exploited.
Read on.