The pcre_exec function in pcre_exec.c in PCRE before 8.38 mishandles a // pattern with a \01 string, which allows remote attackers to cause a denial of service (heap-based buffer overflow) or possibly have unspecified other impact via a crafted regular expression, as demonstrated by a JavaScript RegExp object encountered by Konqueror.
https://security.gentoo.org/glsa/201607-02
https://bto.bluecoat.com/security-advisory/sa128
https://blog.fuzzing-project.org/29-Heap-Overflow-in-PCRE.html
http://www.securityfocus.com/bid/77695
http://lists.fedoraproject.org/pipermail/package-announce/2015-December/173700.html