OpenAM before 16.1.4 does not verify that a signed SAML 1.x assertion or response was signed by the partner named as its issuer, accepting a signature from any certificate in OpenAM's keystore. An attacker holding such a private key, such as a trusted SAML 1.x partner, can forge assertions claiming another partner's issuer and sign in as that partner's users, including privileged ones.
CWE-347