The compile_branch function in PCRE before 8.37 allows context-dependent attackers to compile incorrect code, cause a denial of service (out-of-bounds heap read and crash), or possibly have other unspecified impact via a regular expression with a group containing a forward reference repeated a large number of times within a repeated outer group that has a zero minimum quantifier.

• https://bugs.exim.org/show_bug.cgi?id=1591
• https://fortiguard.com/zeroday/FG-VD-15-015
• http://lists.opensuse.org/opensuse-updates/2015-05/msg00014.html
• https://www.pcre.org/original/changelog.txt

The pcre_compile2 function in PCRE before 8.37 allows context-dependent attackers to compile incorrect code and cause a denial of service (out-of-bounds read) via regular expression with a group containing both a forward referencing subroutine call and a recursive back reference, as demonstrated by "((?+1)(\1))/".

• https://bugs.exim.org/show_bug.cgi?id=1592
• https://fortiguard.com/zeroday/FG-VD-15-016
• http://lists.opensuse.org/opensuse-updates/2015-05/msg00014.html
• https://www.pcre.org/original/changelog.txt

The match function in pcre_exec.c in PCRE before 8.37 mishandles the /(?:((abcd))|(((?:(?:(?:(?:abc|(?:abcdef))))b)abcdefghi)abc)|((*ACCEPT)))/ pattern and related patterns involving (*ACCEPT), which allows remote attackers to obtain sensitive information from process memory or cause a denial of service (partially initialized memory and application crash) via a crafted regular expression, as demonstrated by a JavaScript RegExp object encountered by Konqueror, aka ZDI-CAN-2547.

• https://bugs.exim.org/show_bug.cgi?id=1537
• http://vcs.pcre.org/pcre/code/trunk/ChangeLog?view=markup
• http://vcs.pcre.org/pcre/code/trunk/pcre_exec.c?r1=1502&r2=1510
• https://bugzilla.redhat.com/show_bug.cgi?id=1187225
• http://www.openwall.com/lists/oss-security/2015/08/04/3
• http://www.openwall.com/lists/oss-security/2015/11/29/1
• http://git.php.net/?p=php-src.git;a=commit;h=c351b47ce85a3a147cfa801fa9f0149ab4160834
• http://www.securityfocus.com/bid/76157
• https://bto.bluecoat.com/security-advisory/sa128