A vulnerability was detected in lemonldap-ng up to 2.23.0. Impacted is an unknown function in the library lemonldap-ng-portal/lib/Lemonldap/NG/Portal/CDC.pm of the component SAML Common Domain Cookie Endpoint. Performing a manipulation of the argument url results in open redirect. The attack is possible to be carried out remotely. The exploit is now public and may be used. Applying a patch is the recommended action to fix this issue. The vendor confirms, that "it has been fixed some days ago and will be available in 2.23.1. CDC is quite never used, so the impact is very low."

An issue was discovered in LemonLDAP::NG before 2.20.1. An Improper Check during session refresh allows an authenticated user to raise their authentication level if the admin configured an "Adaptative authentication rule" with an increment instead of an absolute value.

An issue was discovered in LemonLDAP::NG before 2.0.12. There is a missing expiration check in the OAuth2.0 handler, i.e., it does not verify access token validity. An attacker can use a expired access token from an OIDC client to access the OAuth2 handler The earliest affected version is 2.0.4.

Incorrect credential validation in LemonLDAP::NG 2.18.x and 2.19.x before 2.19.2 allows attackers to bypass OAuth2 client authentication via an empty client_password parameter (client secret).

A cross-site scripting (XSS) vulnerability in LemonLDAP::NG before 2.19.3 allows remote attackers to inject arbitrary web script or HTML into the login page via a username if userControl has been set to a non-default value that allows special HTML characters.