Yes, the Orthodox orders and sacraments are valid but those valid sacraments are not profitable unto salvation outside the unity of the Catholic Church, hence the need in the first place for the Orthodox to reunite to Rome (Eastern Catholic Churches).
Extraordinary Magisterium-
“There is but one universal Church of the faithful, outside which no one at all is saved.” (Pope Innocent III, Fourth Lateran Council, 1215.)
“With Faith urging us we are forced to believe and to hold the one, holy, Catholic Church and that, apostolic, and we firmly believe and simply confess this Church outside of which there is no salvation nor remission of sin… Furthermore, we declare, say, define, and proclaim to every human creature that they by absolute necessity for salvation are entirely subject to the Roman Pontiff.”
(Pope Boniface VIII, Unam Sanctam, Nov. 18, 1302)
“The most Holy Roman Church firmly believes, professes and preaches that none of those existing outside the Catholic Church, not only pagans, but also Jews and heretics and schismatics, can have a share in life eternal; but that they will go into the eternal fire which was prepared for the devil and his angels, unless before death they are joined with Her; and that so important is the unity of this ecclesiastical body that only those remaining within this unity can profit by the sacraments of the Church unto salvation, and they alone can receive an eternal recompense for their fasts, their almsgivings, their other works of Christian piety and the duties of a Christian soldier. No one, let his almsgiving be as great as it may, no one, even if he pour out his blood for the Name of Christ, can be saved, unless he remain within the bosom and the unity of the Catholic Church.”*** (Pope Eugene IV, the Bull Cantate Domino, 1441.) ***
Universal Ordinary Magisterium:
The Sacraments, which some people keep and use outside the unity of Christ, are able to preserve the appearance of piety; but the invisible and spiritual virtue of true piety cannot abide there any more than feeling can remain in an amputated part of your body. (Pope Leo XIII: “Exima Nos Laetitia”)
The Church is built on the Rock of Peter, and he who eats the Lamb outside this holy dwelling has no part with God. ***(Pius IX: "Multis Gravibus”) ***
Against these experienced sophists the people must be taught that the profession of the Catholic faith is uniquely true, as the apostle proclaims: one Lord, one faith, one baptism. Jerome used to say it this way: he who eats the lamb outside this house will perish as did those during the flood who were not with Noah in the ark. Indeed, no other name than the name of Jesus is given to men, by which they may be saved. He who believes shall be saved; he who does not believe shall be condemned.
(Traditi Humilitati- On his program for the Pontificate- Encyclical of Pope Pius VIII – May 1829)
#11. In the words of St. Leo, who continues speaking about the Holy See of Peter: “It is necessary that the Church throughout the world be united and cleave to the center of Catholic unity and ecclesiastical communion, so that whoever dares to depart from the unity of Peter might understand that he no longer shares in the divine mystery.” St. Jerome adds: “Whoever eats the lamb outside of this house is unholy. Those who were not in the ark of Noah perished in the flood.” Just as he who does not gather with Christ, so he who does not gather with Christ’s Vicar on earth, clearly scatters. How can someone who destroys the holy authority of the Vicar of Christ and who infringes on his rights gather with him? It is through these rights that the pope is the center of unity, that he has the primacy of order and jurisdiction, and that he has the full power of nurturing, ruling, and governing the universal Church.
(Commissum Dicinitus- On Church and State- Encyclical of Pope Gregory XVI- May 17, 1835)
#5 “Whoever eats the lamb outside of this house is an impious person.”
(Singulari Quidem- On the Church in Austria- Encyclical of Pope Pius IX- March 17, 1856)
There is no salvation outside the Church, and therefore whatever things of the Church are had outside the Church do not avail unto salvation. (Augustine: “On Baptism, Against the Donatists”)