Testcase: http://www.ratp.fr, and pasting (with MMB) a (plain text) address into the "Depart" textarea.

gdb says:
[...]
#3325 0x00007ffff4c3791d in QWidget::event (this=0x12e6350, event=0x7fffff7a31d0) at kernel/qwidget.cpp:8006
#3326 0x00007ffff5111def in QFrame::event (this=0x12e6350, e=0x7fffff7a31d0) at widgets/qframe.cpp:557
#3327 0x00007fffe56faf01 in KHTMLView::widgetEvent (this=0x12e6350, e=0x7fffff7a31d0) at 
/d/kde/src/t/kdelibs/khtml/khtmlview.cpp:2363
#3328 0x00007fffe56fa715 in KHTMLView::eventFilter (this=0x12e6350, o=0x11c9840, e=0x7fffff7a31d0) at 
/d/kde/src/t/kdelibs/khtml/khtmlview.cpp:2208
#3329 0x00007ffff40fa2ab in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=0x62d1e0, receiver=0x11c9840, 
event=0x7fffff7a31d0) at kernel/qcoreapplication.cpp:819
#3330 0x00007ffff4bc3b09 in QApplicationPrivate::notify_helper (this=0x62d1e0, receiver=0x11c9840, e=0x7fffff7a31d0) at 
kernel/qapplication.cpp:4296
#3331 0x00007ffff4bc19da in QApplication::notify (this=0x7fffffffd470, receiver=0x1430d30, e=0x7fffff7a3750) at 
kernel/qapplication.cpp:3865
#3332 0x00007ffff5e89ffb in KApplication::notify (this=0x7fffffffd470, receiver=0x1430d30, event=0x7fffff7a3750) at 
/d/kde/src/t/kdelibs/kdeui/kernel/kapplication.cpp:302
#3333 0x00007ffff40f9f90 in QCoreApplication::notifyInternal (this=0x7fffffffd470, receiver=0x1430d30, event=0x7fffff7a3750) at 
kernel/qcoreapplication.cpp:704
#3334 0x00007fffe570aae3 in QCoreApplication::sendEvent (receiver=0x1430d30, event=0x7fffff7a3750) at /d/qt/4/kde-
qt-4.6/include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#3335 0x00007fffe590ad00 in khtml::RenderWidget::handleEvent (this=0x14506c8, ev=...) at 
/d/kde/src/t/kdelibs/khtml/rendering/render_replaced.cpp:1070
#3336 0x00007fffe5840b26 in DOM::HTMLFrameElementImpl::defaultEventHandler (this=0x16d15f0, e=0x2061350) at 
/d/kde/src/t/kdelibs/khtml/html/html_baseimpl.cpp:297
#3337 0x00007fffe57c7dac in DOM::NodeImpl::dispatchGenericEvent (this=0x16d1600, evt=0x2061350) at 
/d/kde/src/t/kdelibs/khtml/xml/dom_nodeimpl.cpp:526
#3338 0x00007fffe57c7952 in DOM::NodeImpl::dispatchEvent (this=0x16d1600, evt=0x2061350, exceptioncode=@0x7fffff7a3d34, 
tempEvent=true) at /d/kde/src/t/kdelibs/khtml/xml/dom_nodeimpl.cpp:453
#3339 0x00007fffe57040c1 in KHTMLView::dispatchMouseEvent (this=0x12e6350, eventId=7, targetNode=0x16d1600, 
targetNodeNonShared=0x138ddf0, cancelable=false, detail=0, _mouse=0x7fffff7a47d0, setUnder=true, mouseEventType=4, orient=0) at 
/d/kde/src/t/kdelibs/khtml/khtmlview.cpp:3748
#3340 0x00007fffe56f5c29 in KHTMLView::mouseMoveEvent (this=0x12e6350, _mouse=0x7fffff7a47d0) at 
/d/kde/src/t/kdelibs/khtml/khtmlview.cpp:1363
#3341 0x00007ffff4c3791d in QWidget::event (this=0x12e6350, event=0x7fffff7a47d0) at kernel/qwidget.cpp:8006
#3342 0x00007ffff5111def in QFrame::event (this=0x12e6350, e=0x7fffff7a47d0) at widgets/qframe.cpp:557
#3343 0x00007fffe56faf01 in KHTMLView::widgetEvent (this=0x12e6350, e=0x7fffff7a47d0) at 
/d/kde/src/t/kdelibs/khtml/khtmlview.cpp:2363
#3344 0x00007fffe56fa715 in KHTMLView::eventFilter (this=0x12e6350, o=0x11c9840, e=0x7fffff7a47d0) at 
/d/kde/src/t/kdelibs/khtml/khtmlview.cpp:2208
#3345 0x00007ffff40fa2ab in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=0x62d1e0, receiver=0x11c9840, 
event=0x7fffff7a47d0) at kernel/qcoreapplication.cpp:819
[...]

valgrind says nothing, just infinite recursion.

-- 
David Faure, faure@kde.org, http://www.davidfaure.fr
Sponsored by Nokia to work on KDE, incl. Konqueror (http://www.konqueror.org).