aRts 1.5.10 and kdelibs3 3.5.10 and earlier do not properly create temporary directories, which allows local users to hijack the IPC by pre-creating the temporary directory.

KDE kmail before 5.5.2 and messagelib before 5.5.2, as distributed in KDE Applications before 17.04.2, do not ensure that a plugin's sign/encrypt action occurs during use of the Send Later feature, which allows remote attackers to obtain sensitive information by sniffing the network.

KDE kdelibs before 4.14.32 and KAuth before 5.34 allow local users to gain root privileges by spoofing a callerID and leveraging a privileged helper app.

ark before 16.12.1 might allow remote attackers to execute arbitrary code via an executable in an archive, related to associated applications.

kpac/script.cpp in KDE kio before 5.32 and kdelibs before 4.14.30 calls the PAC FindProxyForURL function with a full https URL (potentially including Basic Authentication credentials, a query string, or PATH_INFO), which allows remote attackers to obtain sensitive information via a crafted PAC file.

KMail since version 5.3.0 used a QWebEngine based viewer that had JavaScript enabled. Since the generated html is executed in the local file security context by default access to remote and local URLs was enabled.

Turning all screens off in Plasma-workspace and kscreenlocker while the lock screen is shown can result in the screen being unlocked when turning a screen on again.

A maliciously crafted command line for kdesu can result in the user only seeing part of the commands that will actually get executed as super user.

Through a malicious URL that contained a quote character it was possible to inject HTML code in KMail's plaintext viewer. Due to the parser used on the URL it was not possible to include the equal sign (=) or a space into the injected HTML, which greatly reduces the available HTML functionality. Although it is possible to include an HTML comment indicator to hide content.

KMail since version 5.3.0 used a QWebEngine based viewer that had JavaScript enabled. HTML Mail contents were not sanitized for JavaScript and included code was executed.