According to Security Focus, Ktorrent versions 2.1.3 and below have a security flaw which allows for the remote execution of arbitrary code.
The vulnerabilities were discovered in the components chunkcounter.cpp and torrent.cpp and can be exploited by getting a user to use a modified torrent file, resulting in the possible control of the OS with the same privileges as the Ktorrent user.
There is currently no work-around for the flaws but the situation can be remedied by upgrading to the latest version of Ktorrent, version 2.1.4.
KTorrent is a BitTorrent client written in C++ for KDE, offering mainline DHT and ÂµTorrent compatible peer exchange, port forwarding via UPnP and protocol encryption for getting round those pesky traffic-shaping ISP’s.
KTorrent version 2.2 will be released later this month and will include new features such as multiple tabs, moving finished downloads to another directory, and diskspace preallocation. Another good reason to upgrade!