PCRE before 8.38 mishandles the /(?:|a|){100}x/ pattern and related patterns, which allows remote attackers to cause a denial of service (infinite recursion) or possibly have unspecified other impact via a crafted regular expression, as demonstrated by a JavaScript RegExp object encountered by Konqueror.
https://security.netapp.com/advisory/ntap-20230216-0002/
https://security.gentoo.org/glsa/201607-02
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05240731
https://bto.bluecoat.com/security-advisory/sa128
http://www.securityfocus.com/bid/82990
http://www.openwall.com/lists/oss-security/2015/11/29/1
http://vcs.pcre.org/pcre/code/trunk/ChangeLog?view=markup
http://lists.fedoraproject.org/pipermail/package-announce/2016-January/174931.html