It is reproducible alright.
Here are the core dump and the backtrace (I think  the former is more informative).



> > Context: out of the box  MIDAS (using cmake) on OSX Mojave. 
> > 
> > Running with mongoose/opensslm installation following instruction here:
> > https://midas.triumf.ca/MidasWiki/index.php/Quickstart_Linux
> > 
> > mhttpd crashing when midas webpage opened with Safari (12.1.2). Usually when opening the "chat" tab but sometimes also with the "message" tab.
> > mhttpd(11109,0x70000827a000) malloc: *** error for object 0x7f8669501ef0: pointer being freed was not allocated
> > mhttpd(11109,0x70000827a000) malloc: *** set a breakpoint in malloc_error_break to debug
> > 
> > No crash if using firefox (70.0.1 (64-bit))
> 
> I think we also have reports of mhttpd crash on macos with safari from the Dragon experiment,
> but cannot reproduce the problem.
> 
> If you can reproduce this, can you capture the crash stack trace?
> 
> One way to do this is to enable core dumps in odb "/expt/enable core dumps" set to "y", restart mhttpd,
> wait for the crash. I think macos writes core dumps into /cores/... Or you can run mhttpd inside lldb
> and wait for the crash. the lldb command to show the stack trace is "bt", but you may need
> to switch to different threads to see which one actually crashed. I forget what the command
> for that is.
> 
> BTW, the mhttpd networking code has not changed in a long time, but an update
> of mongoose web server library is overdue (to fix a memory leak, at least).
> 
> K.O.

SnoGlobe:~/packages/midas/build> lldb mhttpd
(lldb) target create "mhttpd"
Current executable set to 'mhttpd' (x86_64).
(lldb) r
Process 15988 launched: '/Users/acquis/packages/midas/bin/mhttpd' (x86_64)
Mongoose web server will use SSL certificate file "/Users/acquis/online/ssl_cert.pem"
Mongoose web server will use authentication realm "snoglobe", password file "/Users/acquis/online/htpasswd.txt"
mongoose web server is redirecting HTTP port 8080 to https://SnoGlobe.local:8443
mongoose web server is listening on the HTTP port 8080
mongoose web server is listening on the HTTPS port 8443
mhttpd(15988,0x70000146e000) malloc: *** error for object 0x100608790: pointer being freed was not allocated
mhttpd(15988,0x70000146e000) malloc: *** set a breakpoint in malloc_error_break to debug
Process 15988 stopped
* thread #2, stop reason = signal SIGABRT
    frame #0: 0x00007fff7456c2c6 libsystem_kernel.dylib`__pthread_kill + 10
libsystem_kernel.dylib`__pthread_kill:
->  0x7fff7456c2c6 <+10>: jae    0x7fff7456c2d0            ; <+20>
    0x7fff7456c2c8 <+12>: movq   %rax, %rdi
    0x7fff7456c2cb <+15>: jmp    0x7fff74566457            ; cerror_nocancel
    0x7fff7456c2d0 <+20>: retq   
Target 0: (mhttpd) stopped.
(lldb) bt
* thread #2, stop reason = signal SIGABRT
  * frame #0: 0x00007fff7456c2c6 libsystem_kernel.dylib`__pthread_kill + 10
    frame #1: 0x00007fff74627bf1 libsystem_pthread.dylib`pthread_kill + 284
    frame #2: 0x00007fff744d66a6 libsystem_c.dylib`abort + 127
    frame #3: 0x00007fff745e5077 libsystem_malloc.dylib`malloc_vreport + 545
    frame #4: 0x00007fff745e4e38 libsystem_malloc.dylib`malloc_report + 151
    frame #5: 0x000000010004fe53 mhttpd`AuthEntry::~AuthEntry(this=0x0000000101300220) at mhttpd.cxx:16983:8
    frame #6: 0x000000010004fe25 mhttpd`AuthEntry::~AuthEntry(this=0x0000000101300220) at mhttpd.cxx:16983:8
    frame #7: 0x000000010004fe09 mhttpd`std::__1::allocator<AuthEntry>::destroy(this=0x00000001001b0f10, __p=0x0000000101300220) at memory:1880:64
    frame #8: 0x000000010004fddd mhttpd`void std::__1::allocator_traits<std::__1::allocator<AuthEntry> >::__destroy<AuthEntry>((null)=std::__1::true_type @ 0x000070000146cc28, __a=0x00000001001b0f10, __p=0x0000000101300220) at memory:1742:18
    frame #9: 0x000000010004fd9d mhttpd`void std::__1::allocator_traits<std::__1::allocator<AuthEntry> >::destroy<AuthEntry>(__a=0x00000001001b0f10, __p=0x0000000101300220) at memory:1595:14
    frame #10: 0x000000010004fd58 mhttpd`std::__1::__vector_base<AuthEntry, std::__1::allocator<AuthEntry> >::__destruct_at_end(this=0x00000001001b0f00, __new_last=0x0000000101300220) at vector:421:9
    frame #11: 0x000000010004fc68 mhttpd`std::__1::__vector_base<AuthEntry, std::__1::allocator<AuthEntry> >::clear(this=0x00000001001b0f00) at vector:364:29
    frame #12: 0x000000010004ff76 mhttpd`std::__1::vector<AuthEntry, std::__1::allocator<AuthEntry> >::clear(this=0x00000001001b0f00 size=1) at vector:766:17
    frame #13: 0x00000001000494d3 mhttpd`read_passwords(auth=0x00000001001b0ec8) at mhttpd.cxx:17047:20
    frame #14: 0x00000001000519d5 mhttpd`handle_http_message(nc=0x0000000100608860, msg=0x000070000146d5a0) at mhttpd.cxx:17719:20
    frame #15: 0x00000001000499e0 mhttpd`handle_http_event_mg(nc=0x0000000100608860, ev=100, ev_data=0x000070000146d5a0) at mhttpd.cxx:17765:7
    frame #16: 0x00000001000650db mhttpd`mg_call(nc=0x0000000100608860, ev_handler=(mhttpd`handle_http_event_mg(mg_connection*, int, void*) at mhttpd.cxx:17760), ev=100, ev_data=0x000070000146d5a0)(mg_connection*, int, void*), int, void*) at mongoose6.cxx:2120:5
    frame #17: 0x000000010006c92b mhttpd`mg_http_call_endpoint_handler(nc=0x0000000100608860, ev=100, hm=0x000070000146d5a0) at mongoose6.cxx:4945:3
    frame #18: 0x000000010006c7c5 mhttpd`mg_http_handler(nc=0x0000000100608860, ev=3, ev_data=0x000070000146dbcc) at mongoose6.cxx:5139:5
    frame #19: 0x00000001000650db mhttpd`mg_call(nc=0x0000000100608860, ev_handler=(mhttpd`mg_http_handler(mg_connection*, int, void*) at mongoose6.cxx:4974), ev=3, ev_data=0x000070000146dbcc)(mg_connection*, int, void*), int, void*) at mongoose6.cxx:2120:5
    frame #20: 0x00000001000670c8 mhttpd`mg_recv_common(nc=0x0000000100608860, buf=0x0000000100801000, len=401) at mongoose6.cxx:2676:3
    frame #21: 0x0000000100066f83 mhttpd`mg_if_recv_tcp_cb(nc=0x0000000100608860, buf=0x0000000100801000, len=401) at mongoose6.cxx:2680:3
    frame #22: 0x0000000100069d32 mhttpd`mg_read_from_socket(conn=0x0000000100608860) at mongoose6.cxx:3378:7
    frame #23: 0x00000001000695f6 mhttpd`mg_mgr_handle_conn(nc=0x0000000100608860, fd_flags=1, now=1573832400.4958119) at mongoose6.cxx:3511:9
    frame #24: 0x0000000100065b74 mhttpd`::mg_mgr_poll(mgr=0x000070000146ded8, timeout_ms=1000) at mongoose6.cxx:3687:5
    frame #25: 0x0000000100076087 mhttpd`per_connection_thread_function(param=0x0000000100608860) at mongoose6.cxx:3805:5
    frame #26: 0x00007fff746252eb libsystem_pthread.dylib`_pthread_body + 126
    frame #27: 0x00007fff74628249 libsystem_pthread.dylib`_pthread_start + 66
    frame #28: 0x00007fff7462440d libsystem_pthread.dylib`thread_start + 13
(lldb) .q