The vulnerability arises when the auth_username_chars setting in OX Dovecot Pro is empty, permitting an attacker to inject arbitrary LDAP filter expressions into the LDAP authentication process. This improper neutralization of special elements in LDAP queries can lead to bypassing authentication restrictions and reconnaissance of the LDAP directory structure. The issue is classified as LDAP injection. The CVSS 3.1 base score is 3.7, reflecting low impact with network attack vector, high attack complexity, no privileges required, no user interaction, unchanged scope, and low confidentiality impact. No known public exploits exist.

Successful exploitation could allow an attacker to bypass certain LDAP authentication restrictions and probe the LDAP directory structure, potentially exposing sensitive directory information. However, the impact on confidentiality is rated low, and there is no impact on integrity or availability. No known exploits are publicly available.

Do not configure auth_username_chars as empty. Alternatively, install a fixed version of OX Dovecot Pro when available. Patch status is not yet confirmed—check the vendor advisory for current remediation guidance.