Version:           4.1.96 (using Devel)
OS:                Linux
Installed from:    Compiled sources

I clicked a link in kmail that opened an https:// link. KDE tried to "validate" the link for me as it always does, by popping up a notification in the notification area, then KDE froze. After a minute, I switched to terminall (tty1) and back and then kded4 said it had crashed.

Backtrace:
Application: KDE Daemon (kded4), signal SIGABRT

Thread 1 (Thread 0xb62126c0 (LWP 6922)):
[KCrash Handler]
#6  0xb80dc430 in __kernel_vsyscall ()
#7  0xb6793880 in raise () from /lib/tls/i686/cmov/libc.so.6
#8  0xb6795248 in abort () from /lib/tls/i686/cmov/libc.so.6
#9  0xb6b75795 in qt_message_output () from /usr/lib/libQtCore.so.4
#10 0xb6b75872 in qFatal () from /usr/lib/libQtCore.so.4
#11 0xb6b75915 in qt_assert () from /usr/lib/libQtCore.so.4
#12 0xb6e407d9 in ?? () from /usr/lib/libkdecore.so.5
#13 0xb6e40cf8 in ?? () from /usr/lib/libkdecore.so.5
#14 0xb6e42fc6 in ?? () from /usr/lib/libkdecore.so.5
#15 0xb6e2a0ba in KConfig::sync () from /usr/lib/libkdecore.so.5
#16 0xb6e32eef in KConfigGroup::sync () from /usr/lib/libkdecore.so.5
#17 0xb41016e7 in ?? () from /usr/lib/kde4/kded_kssld.so
#18 0xb410228b in ?? () from /usr/lib/kde4/kded_kssld.so
#19 0xb6d7626e in ?? () from /usr/lib/libQtDBus.so.4
#20 0xb6d774a7 in ?? () from /usr/lib/libQtDBus.so.4
#21 0xb6d779b1 in ?? () from /usr/lib/libQtDBus.so.4
#22 0xb6d77eaa in ?? () from /usr/lib/libQtDBus.so.4
#23 0xb6c7d771 in QObject::event () from /usr/lib/libQtCore.so.4
#24 0xb71368ec in QApplicationPrivate::notify_helper () from /usr/lib/libQtGui.so.4
#25 0xb713e72e in QApplication::notify () from /usr/lib/libQtGui.so.4
#26 0xb7c5604d in KApplication::notify () from /usr/lib/libkdeui.so.5
#27 0xb6c6de61 in QCoreApplication::notifyInternal () from /usr/lib/libQtCore.so.4
#28 0xb6c6eae5 in QCoreApplicationPrivate::sendPostedEvents () from /usr/lib/libQtCore.so.4
#29 0xb6c6ecdd in QCoreApplication::sendPostedEvents () from /usr/lib/libQtCore.so.4
#30 0xb6c9882f in ?? () from /usr/lib/libQtCore.so.4
#31 0xb65406f8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#32 0xb6543da3 in ?? () from /usr/lib/libglib-2.0.so.0
#33 0xb6543f61 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#34 0xb6c98478 in QEventDispatcherGlib::processEvents () from /usr/lib/libQtCore.so.4
#35 0xb71d0ea5 in ?? () from /usr/lib/libQtGui.so.4
#36 0xb6c6c52a in QEventLoop::processEvents () from /usr/lib/libQtCore.so.4
#37 0xb6c6c6ea in QEventLoop::exec () from /usr/lib/libQtCore.so.4
#38 0xb6c6eda5 in QCoreApplication::exec () from /usr/lib/libQtCore.so.4
#39 0xb7136767 in QApplication::exec () from /usr/lib/libQtGui.so.4
#40 0xb809d996 in kdemain () from /usr/lib/libkdeinit4_kded4.so
#41 0x080486b2 in _start ()