185645 2018-05-15 01:16:52 -0700 null pointer in JSC::jsSubstringOfResolved 2018-05-17 12:50:08 -0700 1 1 1 Unclassified WebKit JavaScriptCore Safari 10 PC iOS 11 NEW P2 Trivial --- 1 zhunkibatu webkit-unassigned ap oldest_to_newest 1423958 0 340396 zhunkibatu 2018-05-15 01:16:52 -0700 Created attachment 340396 poc.js 1 0x7f7beb34ef40 WTFCrash 2 0x7f7be93c88f9 JSC::jsSubstringOfResolved(JSC::VM&, JSC::GCDeferralContext*, JSC::JSString*, unsigned int, unsigned int) 3 0x7f7be9398ee3 JSC::RegExpObject::execInline(JSC::ExecState*, JSC::JSGlobalObject*, JSC::JSString*) 4 0x7f7ba1cfe185 Illegal instruction 1424869 1 ap 2018-05-17 12:50:08 -0700 I cannot reproduce this. Could you please attach a crash log? The version field says Safari 10. That version is old. Does this reproduce for you with Safari 11.1? 340396 2018-05-15 01:16:52 -0700 2018-05-15 01:16:52 -0700 poc.js poc.js application/javascript 59 zhunkibatu ZnVuY3Rpb24gdGVzdCgpIHsKcmV0dXJuICLwoK63Ii5tYXRjaCgvXi4uL3UpOwp9Cgp0ZXN0KCk7 Cgo=