Krishna Yajur Veda 22.214.171.124 prohibit a shudra to perform sacrifice.
was created, the Vairaja Saman, of men the Çudra, of cattle the horse. Therefore the two, the horse and the Çudra, are dependent on others. Therefore the Çudra is not fit for the sacrifice, for he was not created after any gods. Therefore they depend on their feet, for they were created from the feet. The Trivrt is the breaths; the Pañcadaça the half-months; the Saptadaça Prajapati; these worlds are three; the Ekavinça is the sun yonder. In this they rest, in this they find support. He who knows thus rests on this, finds, support in this.
But in Rigveda 10:53:4, all varnas and nishadas are said to perform sacrifice.
Rigveda 10:53:4. This prelude of my speech I now will utter, whereby we Gods may quell our Asura foemen. Eaters of strengthening food who merit worship, O ye Five Tribes (brahimn Kshatriyas, Vaishya, shudra and nishada) , be pleased with mine oblation.
Nirukta 3:8.Ye five-tribes, enjoy my sacrifice. According to some, (the five-tribes) are the gandharvas, the manes, gods, demons, and evil spirits. 'They are the four castes with nisada as the fifth/ says Aupamanyava.3 From what (root) is nisdda (hunter) derived? (He is so called because) he lives by killing animals. Sin is embodied (ni- Vsad) in him,' say the etymologists.
Mahabharata also allow shudras to perform all the duties and sacrifices that are done by Brahmins.
All the four orders, therefore, have always the right to the performance of all pious duties and of sacrifices. Even thus were the four orders at first created equal by Brahman who ordained for all of them (the observances disclosed in) the words of Brahma (in the Vedas). — The Mahabharata, Book 12: Santi Parva: SECTION CLXXXVIII