mod_authnz_external is a tool for creating custom authentication backends for HTTP basic authentication.
mysql/mysql-auth.pl in mod_authnz_external does not properly sanitize input before using it in an SQL query.
A remote attacker could exploit this vulnerability to inject arbitrary SQL statements by using a specially crafted username for HTTP authentication on a site using mod_authnz_external.
There is no known workaround at this time.
All Apache mod_authnz_external users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose ">=www-apache/mod_authnz_external-3.2.6"