Heap-based buffer overflow in the S_regatom function in regcomp.c in Perl 5 before 5.24.3-RC1 and 5.26.x before 5.26.1-RC1 allows remote attackers to cause a denial of service (out-of-bounds write) via a regular expression with a '\N{}' escape and the case-insensitive modifier.
https://www.oracle.com/security-alerts/cpujul2020.html
https://security.netapp.com/advisory/ntap-20180426-0001/
https://rt.perl.org/Public/Bug/Display.html?id=131582
https://perl5.git.perl.org/perl.git/log/refs/tags/v5.26.1-RC1
https://perl5.git.perl.org/perl.git/log/refs/tags/v5.24.3-RC1
https://perl5.git.perl.org/perl.git/commitdiff/96c83ed78aeea1a0496dd2b2d935869a822dc8a5
https://bugzilla.redhat.com/show_bug.cgi?id=1492091