ZITADEL is an open source identity management platform. Prior to 3.4.12 and 4.15.2, ZITADEL's external JWT Identity Provider validates a token's signature and issuer (iss) but not the audience (aud) claim, allowing a validly signed token from a trusted issuer for another relying party to be accepted by ZITADEL. This issue is fixed in versions 3.4.12 and 4.15.2.