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.
http://lists.fedoraproject.org/pipermail/package-announce/2015-December/173700.html