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.