Wordpress is vulnerable to access restriction bypass. The newbloguser
key is a string value which is derived from a userID. Attackers can bypass access restrictions by entering this string.
www.securityfocus.com/bid/102024
codex.wordpress.org/Version_4.9.1
core.trac.wordpress.org/ticket/42713
github.com/WordPress/WordPress/commit/eaf1cfdc1fe0bdffabd8d879c591b864d833326c
lists.debian.org/debian-lts-announce/2017/12/msg00019.html
wordpress.org/news/2017/11/wordpress-4-9-1-security-and-maintenance-release/
wpvulndb.com/vulnerabilities/8969
www.debian.org/security/2018/dsa-4090