Out of bounds read in onig_strcpy() about oniguruma HOT 3 CLOSED

#include <oniguruma.h>
int main()
{
    regex_t *reg;
    unsigned char inp[2] = { '\\', 0xd8 };

    onig_new(&reg, inp, inp + 2, ONIG_OPTION_DEFAULT,
         ONIG_ENCODING_UTF8, ONIG_SYNTAX_DEFAULT, 0);
}

==29231==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fffd81832a2 at pc 0x0000004ab6d5 bp 0x7fffd8181ae0 sp 0x7fffd8181290
READ of size 2 at 0x7fffd81832a2 thread T0
    #0 0x4ab6d4 in __asan_memcpy (/mnt/ram/oniguruma/a.out+0x4ab6d4)
    #1 0x4f276c in onig_strcpy /mnt/ram/oniguruma/src/regparse.c:230:5
    #2 0x4f7856 in onig_node_str_cat /mnt/ram/oniguruma/src/regparse.c:1349:7
    #3 0x4f8531 in node_new_str /mnt/ram/oniguruma/src/regparse.c:1408:7
    #4 0x511fe2 in parse_exp /mnt/ram/oniguruma/src/regparse.c:4911:13
    #5 0x51089b in parse_branch /mnt/ram/oniguruma/src/regparse.c:5205:7
    #6 0x50745d in parse_subexp /mnt/ram/oniguruma/src/regparse.c:5242:7
    #7 0x4faf0f in parse_regexp /mnt/ram/oniguruma/src/regparse.c:5287:7
    #8 0x4fa754 in onig_parse_make_tree /mnt/ram/oniguruma/src/regparse.c:5319:7
    #9 0x53e97f in onig_compile /mnt/ram/oniguruma/src/regcomp.c:5279:7
    #10 0x54ee52 in onig_new /mnt/ram/oniguruma/src/regcomp.c:5518:7
    #11 0x4f21dc in main (/mnt/ram/oniguruma/a.out+0x4f21dc)
    #12 0x7f540f06678f in __libc_start_main /var/tmp/portage/sys-libs/glibc-2.23-r2/work/glibc-2.23/csu/../csu/libc-start.c:289
    #13 0x419708 in _start (/mnt/ram/oniguruma/a.out+0x419708)

Address 0x7fffd81832a2 is located in stack of thread T0 at offset 66 in frame
    #0 0x4f205f in main (/mnt/ram/oniguruma/a.out+0x4f205f)

  This frame has 2 object(s):
    [32, 40) 'reg'
    [64, 66) 'inp' <== Memory access at offset 66 overflows this variable
HINT: this may be a false positive if your program uses some custom stack unwind mechanism or swapcontext
      (longjmp and C++ exceptions *are* supported)
SUMMARY: AddressSanitizer: stack-buffer-overflow (/mnt/ram/oniguruma/a.out+0x4ab6d4) in __asan_memcpy
Shadow bytes around the buggy address:
  0x10007b028600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007b028610: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007b028620: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007b028630: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007b028640: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
=>0x10007b028650: 00 f2 f2 f2[02]f3 f3 f3 00 00 00 00 00 00 00 00
  0x10007b028660: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007b028670: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007b028680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007b028690: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007b0286a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Heap right redzone:      fb
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack partial redzone:   f4
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==29231==ABORTING