CVE-2017-8786 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2017-8786): pcre2test.c in PCRE2 10.23 allows remote attackers to cause a denial of service (heap-based buffer overflow) or possibly have unspecified other impact via a crafted regular expression.
documented at https://blogs.gentoo.org/ago/2017/04/29/libpcre-heap-based-buffer-overflow-write-in-pcre2test-c/ I guess it is A2 instead of C3
Upstream patch: https://vcs.pcre.org/pcre2/code/trunk/src/pcre2test.c?r1=692&r2=697
Fixed in >=dev-libs/libpcre2-10.30, stabilization will happen in bug 617944.
This issue was resolved and addressed in GLSA 201710-09 at https://security.gentoo.org/glsa/201710-09 by GLSA coordinator Aaron Bauman (b-man).