PHP 5.6.15 has been released today (October 29).  The website hasn't posted the announcement or changelog for it yet, but you can see what the changelog is in the NEWS file in git:
http://git.php.net/?p=php-src.git;a=blob;f=NEWS;h=ad9ed260b8da16896e1550d25c45f7790320dfc0;hb=refs/heads/PHP-5.6

It should show up here soon:
http://php.net/ChangeLog-5.php

It fixes several bugs, including several segfault issues.  Some of these may be security issues.

I will be updating php-timezonedb with this update as well.

In the process of building this update, advisory and package list will be as follows for now.

Advisory:
----------------------------------------

The php package has been updated to version 5.6.15, which fixes several bugs.
See the upstream ChangeLog for more details.

References:
http://www.php.net/ChangeLog-5.php#5.6.15

----------------------------------------
Updated packages in core/updates_testing:
----------------------------------------
php-ini-5.6.15-1.mga5
apache-mod_php-5.6.15-1.mga5
php-cli-5.6.15-1.mga5
php-cgi-5.6.15-1.mga5
libphp5_common5-5.6.15-1.mga5
php-devel-5.6.15-1.mga5
php-openssl-5.6.15-1.mga5
php-zlib-5.6.15-1.mga5
php-doc-5.6.15-1.mga5
php-bcmath-5.6.15-1.mga5
php-bz2-5.6.15-1.mga5
php-calendar-5.6.15-1.mga5
php-ctype-5.6.15-1.mga5
php-curl-5.6.15-1.mga5
php-dba-5.6.15-1.mga5
php-dom-5.6.15-1.mga5
php-enchant-5.6.15-1.mga5
php-exif-5.6.15-1.mga5
php-fileinfo-5.6.15-1.mga5
php-filter-5.6.15-1.mga5
php-ftp-5.6.15-1.mga5
php-gd-5.6.15-1.mga5
php-gettext-5.6.15-1.mga5
php-gmp-5.6.15-1.mga5
php-hash-5.6.15-1.mga5
php-iconv-5.6.15-1.mga5
php-imap-5.6.15-1.mga5
php-interbase-5.6.15-1.mga5
php-intl-5.6.15-1.mga5
php-json-5.6.15-1.mga5
php-ldap-5.6.15-1.mga5
php-mbstring-5.6.15-1.mga5
php-mcrypt-5.6.15-1.mga5
php-mssql-5.6.15-1.mga5
php-mysql-5.6.15-1.mga5
php-mysqli-5.6.15-1.mga5
php-mysqlnd-5.6.15-1.mga5
php-odbc-5.6.15-1.mga5
php-opcache-5.6.15-1.mga5
php-pcntl-5.6.15-1.mga5
php-pdo-5.6.15-1.mga5
php-pdo_dblib-5.6.15-1.mga5
php-pdo_firebird-5.6.15-1.mga5
php-pdo_mysql-5.6.15-1.mga5
php-pdo_odbc-5.6.15-1.mga5
php-pdo_pgsql-5.6.15-1.mga5
php-pdo_sqlite-5.6.15-1.mga5
php-pgsql-5.6.15-1.mga5
php-phar-5.6.15-1.mga5
php-posix-5.6.15-1.mga5
php-readline-5.6.15-1.mga5
php-recode-5.6.15-1.mga5
php-session-5.6.15-1.mga5
php-shmop-5.6.15-1.mga5
php-snmp-5.6.15-1.mga5
php-soap-5.6.15-1.mga5
php-sockets-5.6.15-1.mga5
php-sqlite3-5.6.15-1.mga5
php-sybase_ct-5.6.15-1.mga5
php-sysvmsg-5.6.15-1.mga5
php-sysvsem-5.6.15-1.mga5
php-sysvshm-5.6.15-1.mga5
php-tidy-5.6.15-1.mga5
php-tokenizer-5.6.15-1.mga5
php-xml-5.6.15-1.mga5
php-xmlreader-5.6.15-1.mga5
php-xmlrpc-5.6.15-1.mga5
php-xmlwriter-5.6.15-1.mga5
php-xsl-5.6.15-1.mga5
php-wddx-5.6.15-1.mga5
php-zip-5.6.15-1.mga5
php-fpm-5.6.15-1.mga5
phpdbg-5.6.15-1.mga5
php-timezonedb-2015.7-1.mga5

from SRPMS:
php-5.6.15-mga5.src.rpm
php-timezonedb-2015.7-1.mga5.src.rpm

Reproducible: 

Steps to Reproduce: