Thread 1 (Thread 0x7e0cd69e9a00 (LWP 3246)):
[KCrash Handler]
#5  __pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44
#6  0x00007e0cddca8eb3 in __pthread_kill_internal (threadid=<optimized out>, signo=6) at pthread_kill.c:78
#7  0x00007e0cddc50a30 in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26
#8  0x00007e0cddc384c3 in __GI_abort () at abort.c:79
#9  0x00007e0cddc39354 in __libc_message_impl (fmt=fmt@entry=0x7e0cdddc22ea "%s\n") at ../sysdeps/posix/libc_fatal.c:132
#10 0x00007e0cddcb3085 in malloc_printerr (str=str@entry=0x7e0cdddc5220 "malloc_consolidate(): unaligned fastbin chunk detected") at malloc.c:5772
#11 0x00007e0cddcb3dac in malloc_consolidate (av=av@entry=0x7e0cdddf6ac0 <main_arena>) at malloc.c:4846
#12 0x00007e0cddcb64b0 in _int_malloc (av=av@entry=0x7e0cdddf6ac0 <main_arena>, bytes=bytes@entry=16402) at malloc.c:4041
#13 0x00007e0cddcb76f4 in __GI___libc_malloc (bytes=16402) at malloc.c:3336
#14 0x00007e0cdd8519d4 in allocateData (allocSize=<optimized out>) at /usr/src/debug/qt6-base/qtbase/src/corelib/tools/qarraydata.cpp:139
#15 allocateHelper (objectSize=1, alignment=16, capacity=<optimized out>, option=<optimized out>) at /usr/src/debug/qt6-base/qtbase/src/corelib/tools/qarraydata.cpp:181
#16 allocateHelper (objectSize=1, alignment=16, capacity=<optimized out>, option=<optimized out>) at /usr/src/debug/qt6-base/qtbase/src/corelib/tools/qarraydata.cpp:157
#17 QArrayData::allocate1 (dptr=0x7ffc97d02500, capacity=<optimized out>, option=<optimized out>) at /usr/src/debug/qt6-base/qtbase/src/corelib/tools/qarraydata.cpp:211
#18 0x00007e0cdd9f86a4 in QTypedArrayData<char>::allocate (capacity=<optimized out>, option=QArrayData::KeepSize) at /usr/src/debug/qt6-base/qtbase/src/corelib/tools/qarraydata.h:135
#19 QArrayDataPointer<char>::QArrayDataPointer (this=<optimized out>, alloc=<optimized out>, n=<optimized out>, option=QArrayData::KeepSize) at /usr/src/debug/qt6-base/qtbase/src/corelib/tools/qarraydatapointer.h:58
#20 QByteArray::QByteArray(long long, Qt::Initialization) [clone .constprop.0] (this=0x7ffc97d02540, size=16384) at /usr/src/debug/qt6-base/qtbase/src/corelib/text/qbytearray.cpp:1834
#21 0x00007e0cdd88d910 in QRingChunk::QRingChunk (this=0x7ffc97d02540, alloc=<optimized out>) at /usr/src/debug/qt6-base/qtbase/src/corelib/tools/qringbuffer_p.h:34
#22 QRingBuffer::reserve (this=0x591904e449e0, bytes=4) at /usr/src/debug/qt6-base/qtbase/src/corelib/tools/qringbuffer.cpp:115
#23 0x00007e0cdd7092fe in QRingBuffer::append (this=<optimized out>, data=0x7ffc97d02668 "<\001", size=4) at /usr/src/debug/qt6-base/qtbase/src/corelib/tools/qringbuffer.cpp:308
#24 QRingBuffer::append (this=<optimized out>, data=0x7ffc97d02668 "<\001", size=4) at /usr/src/debug/qt6-base/qtbase/src/corelib/tools/qringbuffer.cpp:301
#25 QIODevicePrivate::QRingBufferRef::append (this=0x591904e44938, data=0x7ffc97d02668 "<\001", size=4) at /usr/src/debug/qt6-base/qtbase/src/corelib/io/qiodevice_p.h:85
#26 QFileDevice::writeData (this=0x591904faad70, data=0x7ffc97d02668 "<\001", len=4) at /usr/src/debug/qt6-base/qtbase/src/corelib/io/qfiledevice.cpp:544
#27 0x00007e0cdd718439 in QIODevice::write (this=this@entry=0x591904faad70, data=data@entry=0x7ffc97d02668 "<\001", maxSize=maxSize@entry=4) at /usr/src/debug/qt6-base/qtbase/src/corelib/io/qiodevice.cpp:1703
#28 0x0000591904a52378 in Connection::sendData (this=0x591904faad60, data=...) at /usr/src/debug/plasma-browser-integration/plasma-browser-integration-6.1.0/host/connection.cpp:37
#29 0x0000591904a7533f in AbstractBrowserPlugin::sendReply(int, QJsonObject const&) [clone .isra.0] (requestSerial=requestSerial@entry=1, payload=..., this=<optimized out>) at /usr/src/debug/plasma-browser-integration/plasma-browser-integration-6.1.0/host/abstractbrowserplugin.cpp:54
#30 0x0000591904a53577 in PluginManager::onDataReceived (this=<optimized out>, json=...) at /usr/src/debug/plasma-browser-integration/plasma-browser-integration-6.1.0/host/pluginmanager.cpp:126
#31 0x00007e0cdd7a16f7 in QtPrivate::QSlotObjectBase::call (this=<optimized out>, r=<optimized out>, a=<optimized out>, this=<optimized out>, r=<optimized out>, a=<optimized out>) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qobjectdefs_impl.h:469
#32 doActivate<false> (sender=<optimized out>, signal_index=<optimized out>, argv=<optimized out>) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qobject.cpp:4086
#33 0x0000591904a509cb in Connection::dataReceived (this=0x591904faad60, _t1=...) at /usr/src/debug/plasma-browser-integration/build/host/plasma-browser-integration-host_autogen/include/moc_connection.cpp:141
#34 Connection::readData (this=0x591904faad60) at /usr/src/debug/plasma-browser-integration/plasma-browser-integration-6.1.0/host/connection.cpp:91
#35 0x00007e0cdd7a16f7 in QtPrivate::QSlotObjectBase::call (this=<optimized out>, r=<optimized out>, a=<optimized out>, this=<optimized out>, r=<optimized out>, a=<optimized out>) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qobjectdefs_impl.h:469
#36 doActivate<false> (sender=<optimized out>, signal_index=<optimized out>, argv=<optimized out>) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qobject.cpp:4086
#37 0x00007e0cdd7aa850 in QSocketNotifier::activated (this=0x591904fb1e30, _t1=..., _t2=<optimized out>, _t3=...) at /usr/src/debug/qt6-base/build/src/corelib/Core_autogen/include/moc_qsocketnotifier.cpp:195
#38 QSocketNotifier::event (this=0x591904fb1e30, e=<optimized out>) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qsocketnotifier.cpp:327
#39 0x00007e0cdeafc51c in QApplicationPrivate::notify_helper (this=<optimized out>, receiver=0x591904fb1e30, e=0x7ffc97d02c80) at /usr/src/debug/qt6-base/qtbase/src/widgets/kernel/qapplication.cpp:3287
#40 0x00007e0cdd744d28 in QCoreApplication::notifyInternal2 (receiver=0x591904fb1e30, event=0x7ffc97d02c80) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qcoreapplication.cpp:1142
#41 0x00007e0cdd9a4759 in QCoreApplication::sendEvent (receiver=<optimized out>, event=0x7ffc97d02c80) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qcoreapplication.cpp:1583
#42 socketNotifierSourceDispatch (source=0x591904bf7eb0) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qeventdispatcher_glib.cpp:75
#43 0x00007e0cdbcbea89 in g_main_dispatch (context=0x7e0cd0000f00) at ../glib/glib/gmain.c:3344
#44 0x00007e0cdbd209b7 in g_main_context_dispatch_unlocked (context=0x7e0cd0000f00) at ../glib/glib/gmain.c:4152
#45 g_main_context_iterate_unlocked.isra.0 (context=context@entry=0x7e0cd0000f00, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../glib/glib/gmain.c:4217
#46 0x00007e0cdbcbdf95 in g_main_context_iteration (context=0x7e0cd0000f00, may_block=1) at ../glib/glib/gmain.c:4282
#47 0x00007e0cdd9a2cbd in QEventDispatcherGlib::processEvents (this=0x591904b00000, flags=...) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qeventdispatcher_glib.cpp:394
#48 0x00007e0cdd74f01e in QEventLoop::processEvents (this=0x7ffc97d02f40, flags=...) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qeventloop.cpp:100
#49 QEventLoop::exec (this=0x7ffc97d02f40, flags=...) at /usr/src/debug/qt6-base/qtbase/src/corelib/kernel/qeventloop.cpp:182
#50 0x00007e0cdd74934d in QCoreApplication::exec () at /usr/src/debug/qt6-base/qtbase/src/corelib/global/qflags.h:74
#51 0x00007e0cdeaf83ba in QApplication::exec () at /usr/src/debug/qt6-base/qtbase/src/widgets/kernel/qapplication.cpp:2555
#52 0x0000591904a4ff70 in main (argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/plasma-browser-integration/plasma-browser-integration-6.1.0/host/main.cpp:113

Thanks for the bug report. This looks like a duplicate of 488653 based on the crash output.

*** This bug has been marked as a duplicate of bug 488653 ***