The compile_regex function in pcre_compile.c in PCRE before 8.38 and pcre2_compile.c in PCRE2 before 10.2x mishandles the /(?J:(?|(:(?|(?‘R’)(\k’R’)|((?‘R’)))H’Rk’Rf)|s(?‘R’))))/ and /(?J:(?|(:(?|(?‘R’)(\z(?|(?‘R’)(\k’R’)|((?‘R’)))k’R’)|((?‘R’)))H’Ak’Rf)|s(?‘R’)))/ patterns, and related patterns with certain group references, 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.
rhn.redhat.com/errata/RHSA-2016-2750.html
vcs.pcre.org/pcre/code/trunk/ChangeLog?view=markup
www.openwall.com/lists/oss-security/2015/11/29/1
www.securityfocus.com/bid/76187
access.redhat.com/errata/RHSA-2016:1132
bto.bluecoat.com/security-advisory/sa128
bugs.exim.org/show_bug.cgi?id=1667
bugs.exim.org/show_bug.cgi?id=1672
security.gentoo.org/glsa/201607-02