PCRE before 8.38 mishandles the [: and \\ substrings in character classes, which allows remote attackers to cause a denial of service (uninitialized memory read) or possibly have unspecified other impact via a crafted regular expression, as demonstrated by a JavaScript RegExp object encountered by Konqueror. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-8390