$ ./mjs/build/mjs poc.js
> $ Gmjs poc.js
ASAN:DEADLYSIGNAL
=================================================================
======ERROR: AddressSanitizer: SEGV on unknown address 0x561b4e461e9c (pc 0x561b4e461ed5 bp 0x000000000080 sp 0x7ffdacf6fb18 T0)
======The signal is caused by a WRITE memory access.
#0 0x561b4e461ed4 in free_json_frame src/mjs_json.c:323
#1 0x561b4e461ed4 in mjs_json_parse src/mjs_json.c:476
#2 0x7ffdacf6fc0f (<unknown module>)
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV src/mjs_json.c:323 in free_json_frame
======ABORTING
mJS revision
Commit: b1b6eac
Build platform
Ubuntu 18.04.5 LTS (Linux 5.4.0-44-generic x86_64)
Build steps
Test case
poc.js
Execution steps & Output
Credits: Found by OWL337 team.