The vulnerability CVE-2018-14628 is due to an improper ntSecurityDescriptor on the 'CN=Deleted Objects' LDAP container, allowing information disclosure via the LDAP_SERVER_SHOW_DELETED_OID control. The fix involves running 'samba-tool dbcheck' to correct this descriptor, rather than a code patch to a specific function. While LDAP server functions that handle search requests and access control are involved in the exploitation, the provided information does not point to a specific vulnerable function that was modified. The vulnerability lies in the configuration/data (the descriptor itself) rather than a flaw in a single, identifiable source code function that was directly patched. Therefore, no specific functions can be identified with high confidence from the available information as being directly vulnerable or patched.