According the backtrace, I'd discard #346742, #347050. #347134 and #347139 as duplicates of this one.
Also this one does seem as a duplicate of #343408
HTH,

Application: kontact (4.13.3)
KDE Platform Version: 4.13.3
Qt Version: 4.8.6
Operating System: Linux 3.13.0-59-generic x86_64
Distribution: Ubuntu 14.04.2 LTS

-- Information about the crash:
- What I was doing when the application crashed:

I just wanted to reply to an email (by pressing R). I tried twice with the same specific email. This is not the first time that the problem appears but this is the first time that I meet an email where the crash seems systematic.

The crash can be reproduced every time.

-- Backtrace:
Application: Kontact (kontact), signal: Aborted
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f2760fce800 (LWP 3254))]

Thread 5 (Thread 0x7f273f748700 (LWP 3255)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f275bd7481d in ?? () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#2  0x00007f275bd74859 in ?? () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#3  0x00007f2758496182 in start_thread (arg=0x7f273f748700) at pthread_create.c:312
#4  0x00007f275e54747d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 4 (Thread 0x7f26fee3d700 (LWP 3256)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f275bab520d in ?? () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#2  0x00007f275bda3fd6 in ?? () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#3  0x00007f2758496182 in start_thread (arg=0x7f26fee3d700) at pthread_create.c:312
#4  0x00007f275e54747d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 3 (Thread 0x7f26ef709700 (LWP 3259)):
#0  0x00007f275e53a12d in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f2757fb6fe4 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f2757fb70ec in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f275ecc07be in QEventDispatcherGlib::processEvents (this=0x7f26e80008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:436
#4  0x00007f275ec920af in QEventLoop::processEvents (this=this@entry=0x7f26ef708da0, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007f275ec923a5 in QEventLoop::exec (this=this@entry=0x7f26ef708da0, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007f275eb8ec5f in QThread::exec (this=this@entry=0x26b0d30) at thread/qthread.cpp:537
#7  0x00007f275ec73823 in QInotifyFileSystemWatcherEngine::run (this=0x26b0d30) at io/qfilesystemwatcher_inotify.cpp:265
#8  0x00007f275eb9132f in QThreadPrivate::start (arg=0x26b0d30) at thread/qthread_unix.cpp:349
#9  0x00007f2758496182 in start_thread (arg=0x7f26ef709700) at pthread_create.c:312
#10 0x00007f275e54747d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 2 (Thread 0x7f26ed87a700 (LWP 3272)):
#0  __libc_enable_asynccancel () at ../nptl/sysdeps/unix/sysv/linux/x86_64/cancellation.S:65
#1  0x00007f275e53a122 in poll () at ../sysdeps/unix/syscall-template.S:81
#2  0x00007f2757fb6fe4 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f2757fb70ec in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f275ecc07be in QEventDispatcherGlib::processEvents (this=0x7f26e00008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:436
#5  0x00007f275ec920af in QEventLoop::processEvents (this=this@entry=0x7f26ed879de0, flags=...) at kernel/qeventloop.cpp:149
#6  0x00007f275ec923a5 in QEventLoop::exec (this=this@entry=0x7f26ed879de0, flags=...) at kernel/qeventloop.cpp:204
#7  0x00007f275eb8ec5f in QThread::exec (this=<optimized out>) at thread/qthread.cpp:537
#8  0x00007f275eb9132f in QThreadPrivate::start (arg=0x2222d10) at thread/qthread_unix.cpp:349
#9  0x00007f2758496182 in start_thread (arg=0x7f26ed87a700) at pthread_create.c:312
#10 0x00007f275e54747d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7f2760fce800 (LWP 3254)):
[KCrash Handler]
#6  0x00007f275e483cc9 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#7  0x00007f275e4870d8 in __GI_abort () at abort.c:89
#8  0x00007f275e4c0394 in __libc_message (do_abort=do_abort@entry=1, fmt=fmt@entry=0x7f275e5ceb28 "*** Error in `%s': %s: 0x%s ***\n") at ../sysdeps/posix/libc_fatal.c:175
#9  0x00007f275e4cc66e in malloc_printerr (ptr=<optimized out>, str=0x7f275e5cec58 "double free or corruption (out)", action=1) at malloc.c:4996
#10 _int_free (av=<optimized out>, p=<optimized out>, have_lock=0) at malloc.c:3840
#11 0x00007f275f91e7c5 in free (alignment=8, x=<optimized out>) at ../../include/QtCore/../../src/corelib/tools/qvector.h:99
#12 free (this=<optimized out>, x=<optimized out>) at ../../include/QtCore/../../src/corelib/tools/qvector.h:468
#13 ~QVector (this=0x7fff0d5ce790, __in_chrg=<optimized out>) at ../../include/QtCore/../../src/corelib/tools/qvector.h:124
#14 QTextDocumentLayoutPrivate::layoutTable (this=this@entry=0x7e3bd80, table=0x8055ca0, layoutFrom=layoutFrom@entry=558, layoutTo=layoutTo@entry=558, parentY=..., parentY@entry=...) at text/qtextdocumentlayout.cpp:1596
#15 0x00007f275f91ecd1 in QTextDocumentLayoutPrivate::layoutFrame (this=this@entry=0x7e3bd80, f=f@entry=0x8055ca0, layoutFrom=layoutFrom@entry=558, layoutTo=layoutTo@entry=558, frameWidth=..., frameWidth@entry=..., frameHeight=..., parentY=parentY@entry=...) at text/qtextdocumentlayout.cpp:2120
#16 0x00007f275f91f70d in QTextDocumentLayoutPrivate::layoutFrame (this=this@entry=0x7e3bd80, f=f@entry=0x8055ca0, layoutFrom=layoutFrom@entry=558, layoutTo=layoutTo@entry=558, parentY=...) at text/qtextdocumentlayout.cpp:2062
#17 0x00007f275f920c48 in QTextDocumentLayoutPrivate::layoutFlow (this=this@entry=0x7e3bd80, it=..., layoutStruct=layoutStruct@entry=0x7fff0d5cf2d0, layoutFrom=layoutFrom@entry=558, layoutTo=layoutTo@entry=558, width=..., width@entry=...) at text/qtextdocumentlayout.cpp:2324
#18 0x00007f275f91f03d in QTextDocumentLayoutPrivate::layoutFrame (this=this@entry=0x7e3bd80, f=f@entry=0x82905d0, layoutFrom=layoutFrom@entry=558, layoutTo=layoutTo@entry=558, frameWidth=..., frameWidth@entry=..., frameHeight=..., parentY=parentY@entry=...) at text/qtextdocumentlayout.cpp:2156
#19 0x00007f275f91f70d in QTextDocumentLayoutPrivate::layoutFrame (this=this@entry=0x7e3bd80, f=f@entry=0x82905d0, layoutFrom=layoutFrom@entry=558, layoutTo=layoutTo@entry=558, parentY=parentY@entry=...) at text/qtextdocumentlayout.cpp:2062
#20 0x00007f275f9221c0 in QTextDocumentLayout::doLayout (this=this@entry=0x3be6e30, from=from@entry=558, oldLength=oldLength@entry=1, length=length@entry=0) at text/qtextdocumentlayout.cpp:2952
#21 0x00007f275f9231fe in QTextDocumentLayout::documentChanged (this=0x3be6e30, from=558, oldLength=1, length=0) at text/qtextdocumentlayout.cpp:2915
#22 0x00007f275f900d21 in QTextDocumentPrivate::finishEdit (this=0x7b831f0) at text/qtextdocument_p.cpp:1220
#23 0x00007f275f901264 in QTextDocumentPrivate::endEditBlock (this=<optimized out>) at text/qtextdocument_p.cpp:1201
#24 0x00007f275f9012be in QTextDocumentPrivate::endEditBlock (this=<optimized out>) at text/qtextdocument_p.cpp:1187
#25 0x00007f275f92944b in QTextCursor::removeSelectedText (this=this@entry=0x7fff0d5cf660) at text/qtextcursor.cpp:1662
#26 0x00007f26f7de88e7 in KPIMTextEdit::TextEdit::loadImage (this=0x7ea8690, image=..., matchName=..., resourceName=...) at ../../kpimtextedit/textedit.cpp:521
#27 0x00007f26f46bbdf3 in MessageComposer::ComposerViewBase::collectImages (this=this@entry=0x7bb53e0, root=<optimized out>) at ../../messagecomposer/composer/composerviewbase.cpp:1528
#28 0x00007f26f46bc718 in MessageComposer::ComposerViewBase::setMessage (this=0x7bb53e0, msg=...) at ../../messagecomposer/composer/composerviewbase.cpp:191
#29 0x00007f26f508a928 in KMComposeWin::setMessage (this=this@entry=0x7a599c0, newMsg=..., lastSignState=lastSignState@entry=false, lastEncryptState=lastEncryptState@entry=false, mayAutoSign=mayAutoSign@entry=true, allowDecryption=allowDecryption@entry=false, isModified=isModified@entry=false) at ../../kmail/editor/kmcomposewin.cpp:1602
#30 0x00007f26f509093e in KMComposeWin::KMComposeWin (this=this@entry=0x7a599c0, aMsg=..., lastSignState=lastSignState@entry=false, lastEncryptState=lastEncryptState@entry=false, context=context@entry=KMail::Composer::Reply, id=id@entry=0, textSelection=..., customTemplate=..., __in_chrg=<optimized out>, __vtt_parm=<optimized out>) at ../../kmail/editor/kmcomposewin.cpp:490
#31 0x00007f26f509167b in KMComposeWin::create (msg=..., lastSignState=<optimized out>, lastEncryptState=<optimized out>, context=KMail::Composer::Reply, identity=identity@entry=0, textSelection=..., customTemplate=...) at ../../kmail/editor/kmcomposewin.cpp:181
#32 0x00007f26f50916ac in KMail::makeComposer (msg=..., lastSignState=<optimized out>, lastEncryptState=<optimized out>, context=<optimized out>, identity=identity@entry=0, textSelection=..., customTemplate=...) at ../../kmail/editor/kmcomposewin.cpp:175
#33 0x00007f26f4fc200f in KMReplyCommand::execute (this=0x7a49ba0) at ../../kmail/kmcommands.cpp:833
#34 0x00007f26f4fbcb01 in KMCommand::slotPostTransfer (this=0x7a49ba0, result=KMCommand::OK) at ../../kmail/kmcommands.cpp:267
#35 0x00007f275eca787a in QMetaObject::activate (sender=sender@entry=0x7a49ba0, m=m@entry=0x7f26f53513e0 <KMCommand::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7fff0d5d0240) at kernel/qobject.cpp:3539
#36 0x00007f26f50b5f5e in KMCommand::messagesTransfered (this=this@entry=0x7a49ba0, _t1=_t1@entry=KMCommand::OK) at moc_kmcommands.cpp:116
#37 0x00007f26f4fbe1d3 in KMCommand::slotJobFinished (this=0x7a49ba0) at ../../kmail/kmcommands.cpp:367
#38 0x00007f275eca787a in QMetaObject::activate (sender=sender@entry=0x5bcd8a0, m=m@entry=0x7f275f4ad600 <KJob::staticMetaObject>, local_signal_index=local_signal_index@entry=3, argv=argv@entry=0x7fff0d5d03e0) at kernel/qobject.cpp:3539
#39 0x00007f275f11d6d2 in KJob::result (this=this@entry=0x5bcd8a0, _t1=_t1@entry=0x5bcd8a0) at ./kjob.moc:207
#40 0x00007f275f11d710 in KJob::emitResult (this=0x5bcd8a0) at ../../kdecore/jobs/kjob.cpp:318
#41 0x00007f275ecabc1e in QObject::event (this=0x5bcd8a0, e=<optimized out>) at kernel/qobject.cpp:1194
#42 0x00007f275f685e2c in QApplicationPrivate::notify_helper (this=this@entry=0x1f95a20, receiver=receiver@entry=0x5bcd8a0, e=e@entry=0x7a565e0) at kernel/qapplication.cpp:4567
#43 0x00007f275f68c4a0 in QApplication::notify (this=this@entry=0x7fff0d5d0b10, receiver=receiver@entry=0x5bcd8a0, e=e@entry=0x7a565e0) at kernel/qapplication.cpp:4353
#44 0x00007f2760390d1a in KApplication::notify (this=0x7fff0d5d0b10, receiver=0x5bcd8a0, event=0x7a565e0) at ../../kdeui/kernel/kapplication.cpp:311
#45 0x00007f275ec934dd in QCoreApplication::notifyInternal (this=0x7fff0d5d0b10, receiver=receiver@entry=0x5bcd8a0, event=event@entry=0x7a565e0) at kernel/qcoreapplication.cpp:953
#46 0x00007f275ec96b3d in sendEvent (event=0x7a565e0, receiver=0x5bcd8a0) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#47 QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0, data=0x1f182b0) at kernel/qcoreapplication.cpp:1577
#48 0x00007f275ec96fe3 in QCoreApplication::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0) at kernel/qcoreapplication.cpp:1470
#49 0x00007f275ecc0f83 in sendPostedEvents () at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:236
#50 postEventSourceDispatch (s=0x1f95100) at kernel/qeventdispatcher_glib.cpp:287
#51 0x00007f2757fb6e04 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#52 0x00007f2757fb7048 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#53 0x00007f2757fb70ec in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#54 0x00007f275ecc07a1 in QEventDispatcherGlib::processEvents (this=0x1f19bb0, flags=...) at kernel/qeventdispatcher_glib.cpp:434
#55 0x00007f275f727be6 in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#56 0x00007f275ec920af in QEventLoop::processEvents (this=this@entry=0x7fff0d5d0a10, flags=...) at kernel/qeventloop.cpp:149
#57 0x00007f275ec923a5 in QEventLoop::exec (this=this@entry=0x7fff0d5d0a10, flags=...) at kernel/qeventloop.cpp:204
#58 0x00007f275ec97b79 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1225
#59 0x00007f275f68437c in QApplication::exec () at kernel/qapplication.cpp:3828
#60 0x0000000000403660 in main (argc=1, argv=0x7fff0d5d0c58) at ../../../kontact/src/main.cpp:219

Possible duplicates by query: bug 348699, bug 347427, bug 347139, bug 347134, bug 347050.

This bug has never been confirmed for a Kontact version that is based on KDE Frameworks, except possibly a Technology Preview version 5.0.x. Those versions differ significantly from the old 4.x series. Therefore, I plan to close it in around two or three months. In the meantime, it is set to WAITINGFORINFO to give reporters the opportunity to check if it is still valid. As soon as someone confirms it for a recent version (at least 5.1, ideally even more recent), I'll gladly reopen it.

Please understand that we lack the manpower to triage bugs reported for versions almost two years beyond their end of life.

Just as announced in my last comment, I close this bug. If you encounter it again in a recent version (at least 5.1 aka 15.12; preferably much more recent), please open a new one unless it already exists. Thank you for all your input.