A vulnerability was found in pcre caused by trying to find a Unicode property for a code value greater than 0x10ffff, the Unicode maximum, when running in non-UTF mode (where character values can be up to 0xffffffff).
Upstream bug:
https://bugs.exim.org/showbug.cgi?id=2052
References:
https://blogs.gentoo.org/ago/2017/03/14/libpcre-invalid-memory-read-in-match-pcreexec-c/
Upstream patches (pcre):
https://vcs.pcre.org/pcre?view=revision&revision=1688
Upstream patches (pcre2):
https://vcs.pcre.org/pcre2?view=revision&revision=670