PCRE before 8.38 mishandles the /(?J)(?'d'(?'d'\\g{d}))/ pattern and related patterns with certain recursive back references which allows remote attackers to cause a denial of service (buffer overflow) or possibly have unspecified other impact via a crafted regular expression as demonstrated by a JavaScript RegExp object encountered by Konqueror a related issue to CVE-2015-8392 and CVE-2015-8395.