RabbitMQ: LDAP DN injection via unescaped substitution

RabbitMQ is a messaging and streaming broker. The advisory establishes affected 3.13, 4.0, 4.1, 4.2, and 4.3 maintenance lines but contains conflicting first-fixed versions for the 3.13, 4.0, and 4.1 lines. fill/2 substitutes ${username} into user_dn_pattern without RFC 4514 DN escaping, allowing a crafted username to alter the LDAP bind DN and potentially select a different directory entry. Exploitation requires rabbitmq_auth_backend_ldap with a user_dn_pattern containing ${username}, a directory layout in which the injected suffix resolves usefully, and a password valid for the resulting DN. The advisory body identifies 3.13.15, 4.0.20, 4.1.11, 4.2.9, and 4.3.3 as fixed, while structured metadata identifies 3.13.18, 4.0.23, 4.1.14, 4.2.9, and 4.3.3. No fixed-version assertion is certifiable until a curator resolves this conflict.