Affected: Red Hat Directory Server 11, Red Hat Directory Server 12, Red Hat Directory Server 13, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9

A flaw was found in 389-ds-base. The server does not discard plaintext bytes already buffered from a client connection when negotiating StartTLS, allowing an on-path attacker to inject a crafted LDAP message that is processed after the TLS upgrade and whose response is delivered to the client in place of the client's own pending operation's response, due to messageID collision. This can cause a client application to treat a failed authentication (bind) attempt as successful.