PCRE before 8.38 mishandles the /(?=di(?<=(?1))|(?=(.))))/ pattern and related patterns with an unmatched closing parenthesis, 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.
rhn.redhat.com/errata/RHSA-2016-1025.html
rhn.redhat.com/errata/RHSA-2016-2750.html
vcs.pcre.org/pcre/code/trunk/ChangeLog?view=markup
www-01.ibm.com/support/docview.wss?uid=isg3T1023886
www.openwall.com/lists/oss-security/2015/11/29/1
www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
www.securityfocus.com/bid/85576
access.redhat.com/errata/RHSA-2016:1132
bto.bluecoat.com/security-advisory/sa128
security.gentoo.org/glsa/201607-02