$ ./mjs/build/mjs poc.js
ASAN:DEADLYSIGNAL
=================================================================
==50070==ERROR: AddressSanitizer: SEGV on unknown address 0x3a60d0000001 (pc 0x5588da606950 bp 0x615000000080 sp 0x7ffef6409930 T0)
==50070==The signal is caused by a READ memory access.
#0 0x5588da60694f in gc_compact_strings src/mjs_gc.c:406
#1 0x5588da6087d7 in mjs_gc src/mjs_gc.c:500
#2 0x5588da608ec2 in maybe_gc src/mjs_gc.c:446
#3 0x5588da5d2d67 in mjs_execute src/mjs_exec.c:578
#4 0x5588da5e0a05 in mjs_exec_internal src/mjs_exec.c:1073
#5 0x5588da5e0a05 in mjs_exec_file src/mjs_exec.c:1096
#6 0x5588da59d909 in main src/mjs_main.c:47
#7 0x7fe819cbcb96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)
#8 0x5588da59e449 in _start (/usr/local/bin/mjs+0xe449)
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV src/mjs_gc.c:406 in gc_compact_strings
==50070==ABORTING
mJS revision
Commit: b1b6eac
Build platform
Ubuntu 18.04.5 LTS (Linux 5.4.0-44-generic x86_64)
Build steps
Test case
Execution steps & Output
Credits: Found by OWL337 team.