KMail in KDE 1.0 provides a PGP passphrase as a command line argument to other programs, which could allow local users to obtain the passphrase and compromise the PGP keys of other users by viewing the arguments via programs that list process information, such as ps.

Buffer overflow in kppp in KDE allows local users to gain root access via a long PATH environmental variable.

Buffer overflow in kscreensaver in KDE klock allows local users to gain root privileges via a long HOME environmental variable.

KDE kppp allows local users to create a directory in an arbitrary location via the HOME environmental variable.

KDE klock allows local users to kill arbitrary processes by specifying an arbitrary PID in the .kss.pid file.

KDE allows local users to execute arbitrary commands by setting the KDEDIR environmental variable to modify the search path that KDE uses to locate its executables.

The KDE screen saver in KDE before 3.0.5 does not properly check the return value from a certain function call, which allows attackers with physical access to cause a crash and access the desktop session.

rendering/renderreplaced.cpp in Konqueror in KDE before 4.9.3 allows remote attackers to cause a denial of service (NULL pointer dereference) via a crafted web page, related to "trying to reuse a frame with a null part."