I observed this during a Tether host scan (I can't tell if it's due to Tether or EasyUnlock though). This account has two Tether hosts, and one unlock_key. chrome logs attached as well. I've observed this happening in < 5% of host scans; it's quite rare.

Tim/Kyle, did something change recently in cryptauth/EasyUnlock that might have caused this crash?

Backtrace:

Thread 1 "chrome" received signal SIGSEGV, Segmentation fault.
0x3542e28c in cryptauth::(anonymous namespace)::OnSessionSymmetricKeyDerived(cryptauth::(anonymous namespace)::ValidateResponderAuthMessageContext, std::string const&) () at ../../components/cryptauth/device_to_device_initiator_operations.cc:153
(gdb) bt
#0  0x3542e28c in cryptauth::(anonymous namespace)::OnSessionSymmetricKeyDerived(cryptauth::(anonymous namespace)::ValidateResponderAuthMessageContext, std::string const&) () at ../../components/cryptauth/device_to_device_initiator_operations.cc:153
#1  0x3542e444 in base::internal::Invoker<base::internal::BindState<void (*)(cryptauth::(anonymous namespace)::ValidateResponderAuthMessageContext, std::string const&), cryptauth::(anonymous namespace)::ValidateResponderAuthMessageContext>, void (std::string const&)>::Run(base::internal::BindStateBase*, std::string const&) () at ../../base/bind_internal.h:164
#2  0x33166f86 in chromeos::(anonymous namespace)::EasyUnlockClientImpl::OnData(base::Callback<void (std::string const&), (base::internal::CopyMode)1, (base::internal::RepeatMode)1> const&, dbus::Response*) () at ../../base/callback.h:80
#3  0x332470ac in dbus::ObjectProxy::RunResponseCallback(base::Callback<void (dbus::Response*), (base::internal::CopyMode)1, (base::internal::RepeatMode)1>, base::Callback<void (dbus::ErrorResponse*), (base::internal::CopyMode)1, (base::internal::RepeatMode)1>, base::TimeTicks, DBusMessage*) () at ../../base/callback.h:80
#4  0x332495c0 in base::internal::Invoker<base::internal::BindState<void (dbus::ObjectProxy::*)(base::Callback<void (dbus::Response*), (base::internal::CopyMode)1, (base::internal::RepeatMode)1>, base::Callback<void (dbus::ErrorResponse*), (base::internal::CopyMode)1, (base::internal::RepeatMode)1>, base::TimeTicks, DBusMessage*), scoped_refptr<dbus::ObjectProxy>, base::Callback<void (dbus::Response*), (base::internal::CopyMode)1, (base::internal::RepeatMode)1>, base::Callback<void (dbus::ErrorResponse*), (base::internal::CopyMode)1, (base::internal::RepeatMode)1>, base::TimeTicks, DBusMessage*>, void ()>::Run(base::internal::BindStateBase*) () at ../../base/bind_internal.h:209
#5  0x32adf560 in base::debug::TaskAnnotator::RunTask(char const*, base::PendingTask*) () at ../../base/callback.h:91
#6  0x32a844dc in base::MessageLoop::RunTask(base::PendingTask*) () at ../../base/message_loop/message_loop.cc:422
#7  0x32a847b0 in base::MessageLoop::DeferOrRunPendingTask(base::PendingTask) () at ../../base/message_loop/message_loop.cc:433
#8  0x32a84a74 in base::MessageLoop::DoWork() () at ../../base/message_loop/message_loop.cc:540
#9  0x32a85d5c in base::MessagePumpLibevent::Run(base::MessagePump::Delegate*) () at ../../base/message_loop/message_pump_libevent.cc:219
#10 0x32a9f054 in base::RunLoop::Run() () at ../../base/run_loop.cc:111
#11 0x327f42ce in ChromeBrowserMainParts::MainMessageLoopRun(int*) () at ../../chrome/browser/chrome_browser_main.cc:1962
#12 0x31969e64 in content::BrowserMainLoop::RunMainMessageLoopParts() () at ../../content/browser/browser_main_loop.cc:1147
#13 0x3196bca4 in content::BrowserMainRunnerImpl::Run() () at ../../content/browser/browser_main_runner.cc:142
#14 0x31966976 in content::BrowserMain(content::MainFunctionParams const&) () at ../../content/browser/browser_main.cc:46
#15 0x327d42a4 in content::ContentMainRunnerImpl::Run() () at ../../content/app/content_main_runner.cc:686
#16 0x327ec050 in service_manager::Main(service_manager::MainParams const&) () at ../../services/service_manager/embedder/main.cc:469
#17 0x327d3688 in content::ContentMain(content::ContentMainParams const&) () at ../../content/app/content_main.cc:19
#18 0x31538376 in ChromeMain () at ../../chrome/app/chrome_main.cc:134
#19 0xaec448b8 in __libc_start_main (main=0x0, argc=-1090743560, argv=0x0, init=<optimized out>, fini=0x35f50bfd <__libc_csu_fini>, rtld_fini=0xaf2bbf41 <_dl_fini>, stack_end=0xbefc9454) at libc-start.c:289
#20 0x31538218 in _start ()