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.

OpenID Connect Issuer in LemonLDAP::NG 2.x through 2.0.5 may allow an attacker to bypass access control rules via a crafted OpenID Connect authorization request. To be vulnerable, there must exist an OIDC Relaying party within the LemonLDAP configuration with weaker access control rules than the target RP, and no filtering on redirection URIs.

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.

LemonLDAP::NG -2.0.3 has Incorrect Access Control.

LemonLDAP::NG before 1.2.3 does not use the signature-verification capability of the Lasso library, which allows remote attackers to bypass intended access-control restrictions via crafted SAML data.