In Pivotal Spring-LDAP versions 1.3.0 - 2.3.1, when connected to some LDAP servers, when no additional attributes are bound, and when using LDAP BindAuthenticator with org.springframework.ldap.core.support.DefaultTlsDirContextAuthenticationStrategy as the authentication strategy, and setting userSearch, authentication is allowed with an arbitrary password when the username is correct. This occurs because some LDAP vendors require an explicit operation for the LDAP bind to take effect.
https://www.oracle.com/security-alerts/cpujan2021.html
https://www.debian.org/security/2017/dsa-4046
https://pivotal.io/security/cve-2017-8028
https://lists.debian.org/debian-lts-announce/2017/11/msg00026.html