An issue was discovered in LemonLDAP::NG before 2.0.12. Session cache corruption can lead to authorization bypass or spoofing. By running a loop that makes many authentication attempts, an attacker might alternately be authenticated as one of two different users.

An issue was discovered in LemonLDAP::NG through 2.0.8, when NGINX is used. An attacker may bypass URL-based access control to protected Virtual Hosts by submitting a non-normalized URI. This also affects versions before 0.5.2 of the "Lemonldap::NG handler for Node.js" package.

In LemonLDAP::NG (aka lemonldap-ng) through 2.0.8, validity of the X.509 certificate is not checked by default when connecting to remote LDAP backends, because the default configuration of the Net::LDAPS module for Perl is used.

LemonLDAP::NG before 1.9.20 has an XML External Entity (XXE) issue when submitting a notification to the notification server. By default, the notification server is not enabled and has a "deny all" rule.